[UMA] Use proper C++ objects to serialize tracked_objects across process boundaries.

base/tracked_objects_unittest.cc

Index: base/tracked_objects_unittest.cc
diff --git a/base/tracked_objects_unittest.cc b/base/tracked_objects_unittest.cc
index 0e188b1f45c2e7999d4d94b413f12fde28b56a77..33709b060eb933a760ad84b1f5511114ff0f46bd 100644
--- a/base/tracked_objects_unittest.cc
+++ b/base/tracked_objects_unittest.cc
@@ -6,8 +6,8 @@
 
 #include "base/tracked_objects.h"
 
-#include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/process_util.h"
 #include "base/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -27,23 +27,23 @@ class TrackedObjectsTest : public testing::Test {
     ThreadData::ShutdownSingleThreadedCleanup(false);
   }
 
-  // Provide access, since this class is a friend of ThreadData.
-  void ShutdownSingleThreadedCleanup(bool leak) {
-    ThreadData::ShutdownSingleThreadedCleanup(leak);
+  // Reset the profiler state.
+  void Reset() {

[jar (doing other things), 2012/04/09 23:32:59]

Your name is much better... but I was worried that folks would try to call this
dangerous function without realizing that "it doesn't work" when you're live, in
a multi-threaded scenario.  I think it is fine here in the unit test, but you
should definitely not propogate this further (into the ThreadData class).

[Ilya Sherman, 2012/04/10 00:37:42]

Yeah, I agree that we don't want to propagate this beyond the unit test file.

+    ThreadData::ShutdownSingleThreadedCleanup(false);
   }
 };
 
 TEST_F(TrackedObjectsTest, MinimalStartupShutdown) {
   // Minimal test doesn't even create any tasks.
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   EXPECT_FALSE(ThreadData::first());  // No activity even on this thread.
   ThreadData* data = ThreadData::Get();
   EXPECT_TRUE(ThreadData::first());  // Now class was constructed.
-  EXPECT_TRUE(data);
-  EXPECT_TRUE(!data->next());
+  ASSERT_TRUE(data);
+  EXPECT_FALSE(data->next());
   EXPECT_EQ(data, ThreadData::Get());
   ThreadData::BirthMap birth_map;
   ThreadData::DeathMap death_map;
@@ -52,20 +52,22 @@ TEST_F(TrackedObjectsTest, MinimalStartupShutdown) {
   EXPECT_EQ(0u, birth_map.size());
   EXPECT_EQ(0u, death_map.size());
   EXPECT_EQ(0u, parent_child_set.size());
-  // Cleanup with no leaking.
-  ShutdownSingleThreadedCleanup(false);
+
+  // Clean up with no leaking.
+  Reset();
 
   // Do it again, just to be sure we reset state completely.
-  ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE);
+  EXPECT_TRUE(ThreadData::InitializeAndSetTrackingStatus(
+      ThreadData::PROFILING_CHILDREN_ACTIVE));
   EXPECT_FALSE(ThreadData::first());  // No activity even on this thread.
   data = ThreadData::Get();
   EXPECT_TRUE(ThreadData::first());  // Now class was constructed.
-  EXPECT_TRUE(data);
-  EXPECT_TRUE(!data->next());
+  ASSERT_TRUE(data);
+  EXPECT_FALSE(data->next());
   EXPECT_EQ(data, ThreadData::Get());
   birth_map.clear();
   death_map.clear();
+  parent_child_set.clear();
   data->SnapshotMaps(false, &birth_map, &death_map, &parent_child_set);
   EXPECT_EQ(0u, birth_map.size());
   EXPECT_EQ(0u, death_map.size());
@@ -74,7 +76,7 @@ TEST_F(TrackedObjectsTest, MinimalStartupShutdown) {
 
 TEST_F(TrackedObjectsTest, TinyStartupShutdown) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Instigate tracking on a single tracked object, on our thread.
@@ -83,7 +85,7 @@ TEST_F(TrackedObjectsTest, TinyStartupShutdown) {
 
   ThreadData* data = ThreadData::first();
   ASSERT_TRUE(data);
-  EXPECT_TRUE(!data->next());
+  EXPECT_FALSE(data->next());
   EXPECT_EQ(data, ThreadData::Get());
   ThreadData::BirthMap birth_map;
   ThreadData::DeathMap death_map;
@@ -97,8 +99,7 @@ TEST_F(TrackedObjectsTest, TinyStartupShutdown) {
 
   // Now instigate another birth, while we are timing the run of the first
   // execution.
-  TrackedTime start_time =
-      ThreadData::NowForStartOfRun(first_birth);
+  TrackedTime start_time = ThreadData::NowForStartOfRun(first_birth);
   // Create a child (using the same birth location).
   // TrackingInfo will call TallyABirth() during construction.
   base::TimeTicks kBogusBirthTime;
@@ -140,21 +141,27 @@ TEST_F(TrackedObjectsTest, ParentChildTest) {
   const char* kFile = "FixedUnitTestFileName";
   const char* kFunction = "ParentChildTest";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
+  Births* first_birth = ThreadData::TallyABirthIfActive(location);

[jar (doing other things), 2012/04/09 23:32:59]

Hmm... it looks like I left this out :-(.  Good catch.  Interesting.

 
   // Now instigate another birth, while we are timing the run of the first
   // execution.
-
+  TrackedTime start_time = ThreadData::NowForStartOfRun(first_birth);
   // Create a child (using the same birth location).
   // TrackingInfo will call TallyABirth() during construction.
   base::TimeTicks kBogusBirthTime;
   base::TrackingInfo pending_task(location, kBogusBirthTime);
+  // Finally conclude the outer run.
+  TrackedTime end_time = ThreadData::NowForEndOfRun();
+  ThreadData::TallyRunOnNamedThreadIfTracking(pending_task, start_time,
+                                              end_time);
+
 
   // Don't conclude the run, so that we don't use the actual timer that we

[jar (doing other things), 2012/04/09 23:32:59]

It looks like you concluded the run (contrary to this comment) on line 155.  As
a positive note, you should be able to calculate the duration from (end_time -
start_time).InMilliseconds(), and contrast it with data that you gather.

[Ilya Sherman, 2012/04/10 00:37:42]

Removed this comment in a more recent patch set :)

   // started for the outer profile.  This way the JSON will not include some
   // random time.
   ThreadData* data = ThreadData::first();
   ASSERT_TRUE(data);
-  EXPECT_TRUE(!data->next());
+  EXPECT_FALSE(data->next());
   EXPECT_EQ(data, ThreadData::Get());
 
   ThreadData::BirthMap birth_map;
@@ -164,59 +171,47 @@ TEST_F(TrackedObjectsTest, ParentChildTest) {
   data->SnapshotMaps(false, &birth_map, &death_map, &parent_child_set);
   EXPECT_EQ(1u, birth_map.size());                         // 1 birth location.
   EXPECT_EQ(2, birth_map.begin()->second->birth_count());  // 2 births.
-  EXPECT_EQ(0u, death_map.size());                         // No status yet.
+  EXPECT_EQ(1u, death_map.size());                         // No status yet.
   // Just like TinyStartupShutdown test.
   EXPECT_EQ(1u, parent_child_set.size());                  // 1 child.
   EXPECT_EQ(parent_child_set.begin()->first,
             parent_child_set.begin()->second);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"descendants\":["
-        "{"
-          "\"child_location\":{"
-            "\"file_name\":\"FixedUnitTestFileName\","
-            "\"function_name\":\"ParentChildTest\","
-            "\"line_number\":1776"
-          "},"
-          "\"child_thread\":\"WorkerThread-1\","
-          "\"parent_location\":{"
-            "\"file_name\":\"FixedUnitTestFileName\","
-            "\"function_name\":\"ParentChildTest\","
-            "\"line_number\":1776"
-          "},"
-          "\"parent_thread\":\"WorkerThread-1\""
-        "}"
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"WorkerThread-1\","
-          "\"death_data\":{"
-            "\"count\":2,"
-            "\"queue_ms\":0,"
-            "\"queue_ms_max\":0,"
-            "\"queue_ms_sample\":0,"
-            "\"run_ms\":0,"
-            "\"run_ms_max\":0,"
-            "\"run_ms_sample\":0"
-          "},"
-          "\"death_thread\":\"Still_Alive\","
-          "\"location\":{"
-            "\"file_name\":\"FixedUnitTestFileName\","
-            "\"function_name\":\"ParentChildTest\","
-            "\"line_number\":1776"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(json, birth_only_result);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("WorkerThread-1", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sum);

[jar (doing other things), 2012/04/09 23:32:59]

I *suspect* these times are 0 only because the duration is really small.  I bet
this will turn to a larger number on a slow machine, or when you get unlucky and
the time-calls are made across the border of an timer update.  I'd *suggest* you
calculate the time using end_time and start_time, and use that for most of these
comparisons.

...or am I confused about what is being timed here?

You can "test" my hypothesis by putting a 30ms sleep on line 153.  That should
probably cause this test to fail (currently).

[Ilya Sherman, 2012/04/10 00:37:42]

Good catch!  Fixed.

+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("WorkerThread-1", process_data.tasks[0].death_thread_name);
+
+  ASSERT_EQ(1u, process_data.descendants.size());
+  EXPECT_EQ(kFile, process_data.descendants[0].parent.location.file_name);
+  EXPECT_EQ(kFunction,
+            process_data.descendants[0].parent.location.function_name);
+  EXPECT_EQ(kFakeLineNumber,
+            process_data.descendants[0].parent.location.line_number);
+  EXPECT_EQ("WorkerThread-1", process_data.descendants[0].parent.thread_name);
+  EXPECT_EQ(kFile, process_data.descendants[0].child.location.file_name);
+  EXPECT_EQ(kFunction,
+            process_data.descendants[0].child.location.function_name);
+  EXPECT_EQ(kFakeLineNumber,
+            process_data.descendants[0].child.location.line_number);
+  EXPECT_EQ("WorkerThread-1", process_data.descendants[0].child.thread_name);
 }
 
 TEST_F(TrackedObjectsTest, DeathDataTest) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   scoped_ptr<DeathData> data(new DeathData());
@@ -245,61 +240,39 @@ TEST_F(TrackedObjectsTest, DeathDataTest) {
   EXPECT_EQ(data->queue_duration_sample(), queue_ms);
   EXPECT_EQ(data->count(), 2);
 
-  scoped_ptr<base::DictionaryValue> dictionary(data->ToValue());
-  int integer;
-  EXPECT_TRUE(dictionary->GetInteger("run_ms", &integer));
-  EXPECT_EQ(integer, 2 * run_ms);
-  EXPECT_TRUE(dictionary->GetInteger("run_ms_sample", &integer));
-  EXPECT_EQ(integer, run_ms);
-  EXPECT_TRUE(dictionary->GetInteger("queue_ms", &integer));
-  EXPECT_EQ(integer, 2 * queue_ms);
-  EXPECT_TRUE(dictionary->GetInteger("queue_ms_sample", &integer));
-  EXPECT_EQ(integer, queue_ms);
-  EXPECT_TRUE(dictionary->GetInteger("count", &integer));
-  EXPECT_EQ(integer, 2);
-
-  scoped_ptr<base::Value> value(data->ToValue());
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"count\":2,"
-      "\"queue_ms\":16,"
-      "\"queue_ms_max\":8,"
-      "\"queue_ms_sample\":8,"
-      "\"run_ms\":84,"
-      "\"run_ms_max\":42,"
-      "\"run_ms_sample\":42"
-      "}";
-  EXPECT_EQ(birth_only_result, json);
+  DeathDataSnapshot snapshot(*data);
+  EXPECT_EQ(2, snapshot.count);
+  EXPECT_EQ(2 * run_ms, snapshot.run_duration_sum);
+  EXPECT_EQ(run_ms, snapshot.run_duration_max);
+  EXPECT_EQ(run_ms, snapshot.run_duration_sample);
+  EXPECT_EQ(2 * queue_ms, snapshot.queue_duration_sum);
+  EXPECT_EQ(queue_ms, snapshot.queue_duration_max);
+  EXPECT_EQ(queue_ms, snapshot.queue_duration_sample);
 }
 
-TEST_F(TrackedObjectsTest, DeactivatedBirthOnlyToValueWorkerThread) {
+TEST_F(TrackedObjectsTest, DeactivatedBirthOnlyToSnapshotWorkerThread) {
   // Transition to Deactivated state before doing anything.
   if (!ThreadData::InitializeAndSetTrackingStatus(ThreadData::DEACTIVATED))
     return;
+
   // We don't initialize system with a thread name, so we're viewed as a worker
   // thread.
   const int kFakeLineNumber = 173;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "BirthOnlyToValueWorkerThread";
+  const char* kFunction = "BirthOnlyToSnapshotWorkerThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   Births* birth = ThreadData::TallyABirthIfActive(location);
   // We should now see a NULL birth record.
-  EXPECT_EQ(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_EQ(reinterpret_cast<Births*>(NULL), birth);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-      "]"
-    "}";
-  EXPECT_EQ(json, birth_only_result);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  EXPECT_EQ(0u, process_data.tasks.size());
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-TEST_F(TrackedObjectsTest, DeactivatedBirthOnlyToValueMainThread) {
+TEST_F(TrackedObjectsTest, DeactivatedBirthOnlyToSnapshotMainThread) {
   // Start in the deactivated state.
   if (!ThreadData::InitializeAndSetTrackingStatus(ThreadData::DEACTIVATED))
     return;
@@ -308,130 +281,104 @@ TEST_F(TrackedObjectsTest, DeactivatedBirthOnlyToValueMainThread) {
   ThreadData::InitializeThreadContext("SomeMainThreadName");
   const int kFakeLineNumber = 173;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "BirthOnlyToValueMainThread";
+  const char* kFunction = "BirthOnlyToSnapshotMainThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
   // We expect to not get a birth record.
-  EXPECT_EQ(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_EQ(reinterpret_cast<Births*>(NULL), birth);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-      "]"
-    "}";
-  EXPECT_EQ(json, birth_only_result);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  EXPECT_EQ(0u, process_data.tasks.size());
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-TEST_F(TrackedObjectsTest, BirthOnlyToValueWorkerThread) {
+TEST_F(TrackedObjectsTest, BirthOnlyToSnapshotWorkerThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
+
   // We don't initialize system with a thread name, so we're viewed as a worker
   // thread.
   const int kFakeLineNumber = 173;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "BirthOnlyToValueWorkerThread";
+  const char* kFunction = "BirthOnlyToSnapshotWorkerThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
-
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"WorkerThread-1\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":0,"
-            "\"queue_ms_max\":0,"
-            "\"queue_ms_sample\":0,"
-            "\"run_ms\":0,"
-            "\"run_ms_max\":0,"
-            "\"run_ms_sample\":0"
-          "},"
-          "\"death_thread\":\"Still_Alive\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"BirthOnlyToValueWorkerThread\","
-            "\"line_number\":173"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(json, birth_only_result);
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
+
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("WorkerThread-1", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("Still_Alive", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-TEST_F(TrackedObjectsTest, BirthOnlyToValueMainThread) {
+TEST_F(TrackedObjectsTest, BirthOnlyToSnapshotMainThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Use a well named thread.
   ThreadData::InitializeThreadContext("SomeMainThreadName");
   const int kFakeLineNumber = 173;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "BirthOnlyToValueMainThread";
+  const char* kFunction = "BirthOnlyToSnapshotMainThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
-
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string birth_only_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"SomeMainThreadName\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":0,"
-            "\"queue_ms_max\":0,"
-            "\"queue_ms_sample\":0,"
-            "\"run_ms\":0,"
-            "\"run_ms_max\":0,"
-            "\"run_ms_sample\":0"
-          "},"
-          "\"death_thread\":\"Still_Alive\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"BirthOnlyToValueMainThread\","
-            "\"line_number\":173"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(json, birth_only_result);
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
+
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("SomeMainThreadName", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(0, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("Still_Alive", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-TEST_F(TrackedObjectsTest, LifeCycleToValueMainThread) {
+TEST_F(TrackedObjectsTest, LifeCycleToSnapshotMainThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Use a well named thread.
   ThreadData::InitializeThreadContext("SomeMainThreadName");
   const int kFakeLineNumber = 236;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "LifeCycleToValueMainThread";
+  const char* kFunction = "LifeCycleToSnapshotMainThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
 
-  const base::TimeTicks kTimePosted = base::TimeTicks()
-      + base::TimeDelta::FromMilliseconds(1);
+  const base::TimeTicks kTimePosted = base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(1);
   const base::TimeTicks kDelayedStartTime = base::TimeTicks();
   // TrackingInfo will call TallyABirth() during construction.
   base::TrackingInfo pending_task(location, kDelayedStartTime);
@@ -443,57 +390,46 @@ TEST_F(TrackedObjectsTest, LifeCycleToValueMainThread) {
   ThreadData::TallyRunOnNamedThreadIfTracking(pending_task,
       kStartOfRun, kEndOfRun);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"SomeMainThreadName\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":4,"
-            "\"queue_ms_max\":4,"
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":2,"
-            "\"run_ms_max\":2,"
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"SomeMainThreadName\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"LifeCycleToValueMainThread\","
-            "\"line_number\":236"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("SomeMainThreadName", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("SomeMainThreadName", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
 // We will deactivate tracking after the birth, and before the death, and
 // demonstrate that the lifecycle is completely tallied. This ensures that
 // our tallied births are matched by tallied deaths (except for when the
 // task is still running, or is queued).
-TEST_F(TrackedObjectsTest, LifeCycleMidDeactivatedToValueMainThread) {
+TEST_F(TrackedObjectsTest, LifeCycleMidDeactivatedToSnapshotMainThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Use a well named thread.
   ThreadData::InitializeThreadContext("SomeMainThreadName");
   const int kFakeLineNumber = 236;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "LifeCycleToValueMainThread";
+  const char* kFunction = "LifeCycleToSnapshotMainThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
 
-  const base::TimeTicks kTimePosted = base::TimeTicks()
-      + base::TimeDelta::FromMilliseconds(1);
+  const base::TimeTicks kTimePosted = base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(1);
   const base::TimeTicks kDelayedStartTime = base::TimeTicks();
   // TrackingInfo will call TallyABirth() during construction.
   base::TrackingInfo pending_task(location, kDelayedStartTime);
@@ -509,39 +445,28 @@ TEST_F(TrackedObjectsTest, LifeCycleMidDeactivatedToValueMainThread) {
   ThreadData::TallyRunOnNamedThreadIfTracking(pending_task,
       kStartOfRun, kEndOfRun);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"SomeMainThreadName\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":4,"
-            "\"queue_ms_max\":4,"
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":2,"
-            "\"run_ms_max\":2,"
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"SomeMainThreadName\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"LifeCycleToValueMainThread\","
-            "\"line_number\":236"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("SomeMainThreadName", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("SomeMainThreadName", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
 // We will deactivate tracking before starting a life cycle, and neither
 // the birth nor the death will be recorded.
-TEST_F(TrackedObjectsTest, LifeCyclePreDeactivatedToValueMainThread) {
+TEST_F(TrackedObjectsTest, LifeCyclePreDeactivatedToSnapshotMainThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(ThreadData::DEACTIVATED))
     return;
 
@@ -549,14 +474,14 @@ TEST_F(TrackedObjectsTest, LifeCyclePreDeactivatedToValueMainThread) {
   ThreadData::InitializeThreadContext("SomeMainThreadName");
   const int kFakeLineNumber = 236;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "LifeCycleToValueMainThread";
+  const char* kFunction = "LifeCycleToSnapshotMainThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
   EXPECT_EQ(birth, reinterpret_cast<Births*>(NULL));
 
-  const base::TimeTicks kTimePosted = base::TimeTicks()
-      + base::TimeDelta::FromMilliseconds(1);
+  const base::TimeTicks kTimePosted = base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(1);
   const base::TimeTicks kDelayedStartTime = base::TimeTicks();
   // TrackingInfo will call TallyABirth() during construction.
   base::TrackingInfo pending_task(location, kDelayedStartTime);
@@ -568,21 +493,16 @@ TEST_F(TrackedObjectsTest, LifeCyclePreDeactivatedToValueMainThread) {
   ThreadData::TallyRunOnNamedThreadIfTracking(pending_task,
       kStartOfRun, kEndOfRun);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  EXPECT_EQ(0u, process_data.tasks.size());
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-TEST_F(TrackedObjectsTest, LifeCycleToValueWorkerThread) {
+TEST_F(TrackedObjectsTest, LifeCycleToSnapshotWorkerThread) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Don't initialize thread, so that we appear as a worker thread.
@@ -590,11 +510,11 @@ TEST_F(TrackedObjectsTest, LifeCycleToValueWorkerThread) {
 
   const int kFakeLineNumber = 236;
   const char* kFile = "FixedFileName";
-  const char* kFunction = "LifeCycleToValueWorkerThread";
+  const char* kFunction = "LifeCycleToSnapshotWorkerThread";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
 
   const TrackedTime kTimePosted = TrackedTime() + Duration::FromMilliseconds(1);
   const TrackedTime kStartOfRun = TrackedTime() +
@@ -603,78 +523,82 @@ TEST_F(TrackedObjectsTest, LifeCycleToValueWorkerThread) {
   ThreadData::TallyRunOnWorkerThreadIfTracking(birth, kTimePosted,
       kStartOfRun, kEndOfRun);
 
-  // Call for the ToValue, but tell it to not the maxes after scanning.
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"WorkerThread-1\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":4,"
-            "\"queue_ms_max\":4,"
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":2,"
-            "\"run_ms_max\":2,"
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"WorkerThread-1\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"LifeCycleToValueWorkerThread\","
-            "\"line_number\":236"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
-
-  // Call for the ToValue, but tell it to reset the maxes after scanning.
+  // Call for the ToSnapshot, but tell it to not reset the maxes after scanning.
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("WorkerThread-1", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("WorkerThread-1", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
+
+  // Call for the ToSnapshot, but tell it to reset the maxes after scanning.
   // We'll still get the same values, but the data will be reset (which we'll
   // see in a moment).
-  value.reset(ThreadData::ToValue(true));
-  base::JSONWriter::Write(value.get(), &json);
-  // Result should be unchanged.
-  EXPECT_EQ(one_line_result, json);
-
-  // Call for the ToValue, and now we'll see the result of the last translation,
-  // as the max will have been pushed back to zero.
-  value.reset(ThreadData::ToValue(false));
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result_with_zeros = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"WorkerThread-1\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":4,"
-            "\"queue_ms_max\":0,"  // Note zero here.
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":2,"
-            "\"run_ms_max\":0,"   // Note zero here.
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"WorkerThread-1\","
-          "\"location\":{"
-            "\"file_name\":\"FixedFileName\","
-            "\"function_name\":\"LifeCycleToValueWorkerThread\","
-            "\"line_number\":236"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result_with_zeros, json);
+  ProcessDataSnapshot process_data_pre_reset;
+  ThreadData::Snapshot(true, &process_data_pre_reset);
+  ASSERT_EQ(1u, process_data_pre_reset.tasks.size());
+  EXPECT_EQ(kFile, process_data_pre_reset.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction,
+            process_data_pre_reset.tasks[0].birth.location.function_name);
+  EXPECT_EQ(
+      kFakeLineNumber,
+      process_data_pre_reset.tasks[0].birth.location.line_number);
+  EXPECT_EQ("WorkerThread-1",
+            process_data_pre_reset.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data_pre_reset.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data_pre_reset.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data_pre_reset.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data_pre_reset.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data_pre_reset.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data_pre_reset.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4,
+            process_data_pre_reset.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("WorkerThread-1",
+            process_data_pre_reset.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data_pre_reset.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data_pre_reset.process_id);
+
+  // Call for the ToSnapshot, and now we'll see the result of the last
+  // translation, as the max will have been pushed back to zero.
+  ProcessDataSnapshot process_data_post_reset;
+  ThreadData::Snapshot(true, &process_data_post_reset);
+  ASSERT_EQ(1u, process_data_post_reset.tasks.size());
+  EXPECT_EQ(kFile, process_data_post_reset.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction,
+            process_data_post_reset.tasks[0].birth.location.function_name);
+  EXPECT_EQ(
+      kFakeLineNumber,
+      process_data_post_reset.tasks[0].birth.location.line_number);
+  EXPECT_EQ("WorkerThread-1",
+            process_data_post_reset.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data_post_reset.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data_post_reset.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(0, process_data_post_reset.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data_post_reset.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data_post_reset.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(0, process_data_post_reset.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4,
+            process_data_post_reset.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("WorkerThread-1",
+            process_data_post_reset.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data_post_reset.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data_post_reset.process_id);
 }
 
 TEST_F(TrackedObjectsTest, TwoLives) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Use a well named thread.
@@ -685,11 +609,11 @@ TEST_F(TrackedObjectsTest, TwoLives) {
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
   // Do not delete birth.  We don't own it.
   Births* birth = ThreadData::TallyABirthIfActive(location);
-  EXPECT_NE(birth, reinterpret_cast<Births*>(NULL));
+  EXPECT_NE(reinterpret_cast<Births*>(NULL), birth);
 
 
-  const base::TimeTicks kTimePosted = base::TimeTicks()
-      + base::TimeDelta::FromMilliseconds(1);
+  const base::TimeTicks kTimePosted = base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(1);
   const base::TimeTicks kDelayedStartTime = base::TimeTicks();
   // TrackingInfo will call TallyABirth() during construction.
   base::TrackingInfo pending_task(location, kDelayedStartTime);
@@ -708,39 +632,28 @@ TEST_F(TrackedObjectsTest, TwoLives) {
   ThreadData::TallyRunOnNamedThreadIfTracking(pending_task2,
       kStartOfRun, kEndOfRun);
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"SomeFileThreadName\","
-          "\"death_data\":{"
-            "\"count\":2,"
-            "\"queue_ms\":8,"
-            "\"queue_ms_max\":4,"
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":4,"
-            "\"run_ms_max\":2,"
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"SomeFileThreadName\","
-          "\"location\":{"
-            "\"file_name\":\"AnotherFileName\","
-            "\"function_name\":\"TwoLives\","
-            "\"line_number\":222"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(1u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("SomeFileThreadName", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(8, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("SomeFileThreadName", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
 TEST_F(TrackedObjectsTest, DifferentLives) {
   if (!ThreadData::InitializeAndSetTrackingStatus(
-      ThreadData::PROFILING_CHILDREN_ACTIVE))
+          ThreadData::PROFILING_CHILDREN_ACTIVE))
     return;
 
   // Use a well named thread.
@@ -750,8 +663,8 @@ TEST_F(TrackedObjectsTest, DifferentLives) {
   const char* kFunction = "DifferentLives";
   Location location(kFunction, kFile, kFakeLineNumber, NULL);
 
-  const base::TimeTicks kTimePosted = base::TimeTicks()
-      + base::TimeDelta::FromMilliseconds(1);
+  const base::TimeTicks kTimePosted = base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(1);
   const base::TimeTicks kDelayedStartTime = base::TimeTicks();
   // TrackingInfo will call TallyABirth() during construction.
   base::TrackingInfo pending_task(location, kDelayedStartTime);
@@ -770,53 +683,36 @@ TEST_F(TrackedObjectsTest, DifferentLives) {
   base::TrackingInfo pending_task2(second_location, kDelayedStartTime);
   pending_task2.time_posted = kTimePosted;  // Overwrite implied Now().
 
-  scoped_ptr<base::Value> value(ThreadData::ToValue(false));
-  std::string json;
-  base::JSONWriter::Write(value.get(), &json);
-  std::string one_line_result = "{"
-      "\"descendants\":["
-      "],"
-      "\"list\":["
-        "{"
-          "\"birth_thread\":\"SomeFileThreadName\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":4,"
-            "\"queue_ms_max\":4,"
-            "\"queue_ms_sample\":4,"
-            "\"run_ms\":2,"
-            "\"run_ms_max\":2,"
-            "\"run_ms_sample\":2"
-          "},"
-          "\"death_thread\":\"SomeFileThreadName\","
-          "\"location\":{"
-            "\"file_name\":\"AnotherFileName\","
-            "\"function_name\":\"DifferentLives\","
-            "\"line_number\":567"
-          "}"
-        "},"
-        "{"
-          "\"birth_thread\":\"SomeFileThreadName\","
-          "\"death_data\":{"
-            "\"count\":1,"
-            "\"queue_ms\":0,"
-            "\"queue_ms_max\":0,"
-            "\"queue_ms_sample\":0,"
-            "\"run_ms\":0,"
-            "\"run_ms_max\":0,"
-            "\"run_ms_sample\":0"
-          "},"
-          "\"death_thread\":\"Still_Alive\","
-          "\"location\":{"
-            "\"file_name\":\"AnotherFileName\","
-            "\"function_name\":\"DifferentLives\","
-            "\"line_number\":999"
-          "}"
-        "}"
-      "]"
-    "}";
-  EXPECT_EQ(one_line_result, json);
+  ProcessDataSnapshot process_data;
+  ThreadData::Snapshot(false, &process_data);
+  ASSERT_EQ(2u, process_data.tasks.size());
+  EXPECT_EQ(kFile, process_data.tasks[0].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[0].birth.location.function_name);
+  EXPECT_EQ(kFakeLineNumber, process_data.tasks[0].birth.location.line_number);
+  EXPECT_EQ("SomeFileThreadName", process_data.tasks[0].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[0].death_data.count);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sum);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_max);
+  EXPECT_EQ(2, process_data.tasks[0].death_data.run_duration_sample);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sum);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_max);
+  EXPECT_EQ(4, process_data.tasks[0].death_data.queue_duration_sample);
+  EXPECT_EQ("SomeFileThreadName", process_data.tasks[0].death_thread_name);
+  EXPECT_EQ(kFile, process_data.tasks[1].birth.location.file_name);
+  EXPECT_EQ(kFunction, process_data.tasks[1].birth.location.function_name);
+  EXPECT_EQ(kSecondFakeLineNumber,
+            process_data.tasks[1].birth.location.line_number);
+  EXPECT_EQ("SomeFileThreadName", process_data.tasks[1].birth.thread_name);
+  EXPECT_EQ(1, process_data.tasks[1].death_data.count);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.run_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.run_duration_max);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.run_duration_sample);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.queue_duration_sum);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.queue_duration_max);
+  EXPECT_EQ(0, process_data.tasks[1].death_data.queue_duration_sample);
+  EXPECT_EQ("Still_Alive", process_data.tasks[1].death_thread_name);
+  EXPECT_EQ(0u, process_data.descendants.size());
+  EXPECT_EQ(base::GetCurrentProcId(), process_data.process_id);
 }
 
-
 }  // namespace tracked_objects