Fix TraceEventTestFixture flakiness

base/debug/trace_event_unittest.cc

Index: base/debug/trace_event_unittest.cc
diff --git a/base/debug/trace_event_unittest.cc b/base/debug/trace_event_unittest.cc
index 5d32f2f606df9e41bf08fc1f02613f1d3b04802e..f806cf1928e870dd1ba637f3cb14ba05e13cb160 100644
--- a/base/debug/trace_event_unittest.cc
+++ b/base/debug/trace_event_unittest.cc
@@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/debug/trace_event.h"
+#include "base/debug/trace_event_unittest.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/debug/trace_event.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/memory/ref_counted_memory.h"
@@ -20,6 +21,8 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+using base::debug::HighResSleepForTraceTest;
+
 namespace base {
 namespace debug {
 
@@ -633,6 +636,13 @@ void TraceCallsWithCachedCategoryPointersPointers(const char* name_str) {
 
 }  // namespace
 
+void HighResSleepForTraceTest(base::TimeDelta elapsed) {
+  base::TimeTicks end_time = base::TimeTicks::HighResNow() + elapsed;
+  do {
+    base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(1));

[jar (doing other things), 2012/08/16 01:23:35]

As per our discussion... it is very alarming that ::Sleep() can return a full
10ms too soon... and you had to try to play this game....

It will be very interesting to see if this really cures the flakyness that would
otherwise appear around line 856 of this (modified) file.

+  } while (base::TimeTicks::HighResNow() < end_time);
+}
+
 // Simple Test for emitting data and validating it was received.
 TEST_F(TraceEventTestFixture, DataCaptured) {
   ManualTestSetUp();
@@ -843,7 +853,7 @@ TEST_F(TraceEventTestFixture, DataCapturedThreshold) {
     // 100+ seconds to avoid flakiness.
     TRACE_EVENT_IF_LONGER_THAN0(100000000, "time", "threshold long1");
     TRACE_EVENT_IF_LONGER_THAN0(200000000, "time", "threshold long2");
-    base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(20));
+    HighResSleepForTraceTest(base::TimeDelta::FromMilliseconds(20));
   }
 
   // Test that a normal nested event remains after it's parent event is dropped.
@@ -868,8 +878,7 @@ TEST_F(TraceEventTestFixture, DataCapturedThreshold) {
             TRACE_EVENT_IF_LONGER_THAN0(1000, "time", "3threshold1000");
             {
               TRACE_EVENT_IF_LONGER_THAN0(100, "time", "3threshold100");
-              base::PlatformThread::Sleep(
-                  base::TimeDelta::FromMilliseconds(20));
+              HighResSleepForTraceTest(base::TimeDelta::FromMilliseconds(20));
             }
           }
         }
@@ -893,8 +902,7 @@ TEST_F(TraceEventTestFixture, DataCapturedThreshold) {
             {
               TRACE_EVENT_IF_LONGER_THAN0(200000000, "time",
                                           "4thresholdlong2");
-              base::PlatformThread::Sleep(
-                  base::TimeDelta::FromMilliseconds(20));
+              HighResSleepForTraceTest(base::TimeDelta::FromMilliseconds(20));
             }
           }
         }