Added asynchronous notification of readiness to the StatisticsProvider, and

chrome/browser/metrics/metrics_service.cc

Index: chrome/browser/metrics/metrics_service.cc
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index c691f70268c9ebff8018cb199862dd7ed64c8ed1..da8afb5377f99f97f66fb88dd771df3540e19055 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -89,11 +89,10 @@
 // initial log.
 //
 //    INIT_TASK_SCHEDULED,    // Waiting for deferred init tasks to complete.
-// Typically about 30 seconds after startup, a task is sent to a second thread
-// (the file thread) to perform deferred (lower priority and slower)
-// initialization steps such as getting the list of plugins.  That task will
-// (when complete) make an async callback (via a Task) to indicate the
-// completion.
+// Typically about 30 seconds after startup, a task is posted to perform
+// deferred (lower priority and slower) initialization steps such as getting the
+// list of plugins.  That task will (when complete) make an async callback (via
+// a Task) to indicate the completion.
 //
 //    INIT_TASK_DONE,         // Waiting for timer to send initial log.
 // The callback has arrived, and it is now possible for an initial log to be
@@ -199,7 +198,6 @@
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "chrome/browser/chromeos/external_metrics.h"
-#include "chrome/browser/chromeos/system/statistics_provider.h"
 #endif
 
 using base::Time;
@@ -222,6 +220,10 @@ bool IsSingleThreaded() {
 // initialization work.
 const int kInitializationDelaySeconds = 30;
 
+// The timeout, in seconds, to resume initialization of the MetricsService if
+// the initialization of the StatisticsProvider hasn't completed yet.
+const int kStatisticsProviderTimeoutSeconds = 300;
+
 // This specifies the amount of time to wait for all renderers to send their
 // data.
 const int kMaxHistogramGatheringWaitDuration = 60000;  // 60 seconds.
@@ -243,6 +245,11 @@ const int kSaveStateIntervalMinutes = 5;
 // e.g., the server is down.
 const int kNoResponseCode = content::URLFetcher::RESPONSE_CODE_INVALID - 1;
 
+// Used to indicate that a report was generated before the hardware_class
+// property was available from the StatisticsProvider. This is used to identify
+// faulty reports from Chrome OS clients.
+const char kHardwareClassNotReady[] = "(not ready)";
+
 }
 
 // static
@@ -406,6 +413,9 @@ MetricsService::MetricsService()
 
 MetricsService::~MetricsService() {
   SetRecording(false);
+#if defined(OS_CHROMEOS)
+  chromeos::system::StatisticsProvider::GetInstance()->RemoveObserver(this);
+#endif
 }
 
 void MetricsService::Start() {
@@ -750,32 +760,65 @@ void MetricsService::InitializeMetricsState() {
   ScheduleNextStateSave();
 }
 
-// static
-void MetricsService::InitTaskGetHardwareClass(
-    base::WeakPtr<MetricsService> self,
-    base::MessageLoopProxy* target_loop) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+void MetricsService::InitTaskGetHardwareClass() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_EQ(INIT_TASK_SCHEDULED, state_);
 
-  std::string hardware_class;
 #if defined(OS_CHROMEOS)
+  // Exactly one of these two callbacks will be invoked. |timeout_callback_|
+  // is posted to UI with a certain delay; |on_ready_callback_| is invoked
+  // once the StatisticsProvider() becomes ready. Execution of one of these
+  // callbacks cancels the execution of the other.
+  timeout_callback_.Reset(
+      base::Bind(&MetricsService::OnStatisticsProviderTimeout,
+                 base::Unretained(this)));
+  on_ready_callback_.Reset(
+      base::Bind(&MetricsService::InitTaskGetPluginInfo,
+                 base::Unretained(this)));
+
+  BrowserThread::PostDelayedTask(
+      BrowserThread::UI, FROM_HERE,
+      timeout_callback_.callback(),
+      base::TimeDelta::FromSeconds(kStatisticsProviderTimeoutSeconds));
+
+  // The hardware class can only be retrieved once the StatisticsProvider is
+  // ready. This usually happens early enough, but can take longer on some
+  // faulty hardware.
+  chromeos::system::StatisticsProvider::GetInstance()->AddObserver(this);
+#else
+  InitTaskGetPluginInfo();
+#endif

[Ilya Sherman, 2012/05/16 01:01:17]

nit: Please add " // #if defined(OS_CHROMEOS)"

[Joao da Silva, 2012/05/16 12:53:34]

Done.

+}
+
+#if defined(OS_CHROMEOS)
+
+void MetricsService::OnMachineStatisticsReady() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   chromeos::system::StatisticsProvider::GetInstance()->GetMachineStatistic(
-      "hardware_class", &hardware_class);
-#endif  // OS_CHROMEOS
+      "hardware_class", &hardware_class_);
+  timeout_callback_.Cancel();
+  if (!on_ready_callback_.IsCancelled())
+    on_ready_callback_.callback().Run();
+}
 
-  target_loop->PostTask(FROM_HERE,
-      base::Bind(&MetricsService::OnInitTaskGotHardwareClass,
-          self, hardware_class));
+void MetricsService::OnStatisticsProviderTimeout() {

[Ilya Sherman, 2012/05/16 01:01:17]

nit: DCHECK to make sure we're still on the UI thread?

[Joao da Silva, 2012/05/16 12:53:34]

Done.

+  // Use an invalid hardware_class temporarily until the StatisticsProvider is
+  // ready.
+  hardware_class_ = kHardwareClassNotReady;
+  on_ready_callback_.Cancel();
+  InitTaskGetPluginInfo();
 }
 
-void MetricsService::OnInitTaskGotHardwareClass(
-    const std::string& hardware_class) {
+#endif

[Ilya Sherman, 2012/05/16 01:01:17]

nit: Ditto

[Joao da Silva, 2012/05/16 12:53:34]

Done.

+
+void MetricsService::InitTaskGetPluginInfo() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK_EQ(INIT_TASK_SCHEDULED, state_);
-  hardware_class_ = hardware_class;
 
   // Start the next part of the init task: loading plugin information.
   PluginService::GetInstance()->GetPlugins(
       base::Bind(&MetricsService::OnInitTaskGotPluginInfo,
-          self_ptr_factory_.GetWeakPtr()));
+                 self_ptr_factory_.GetWeakPtr()));
 }
 
 void MetricsService::OnInitTaskGotPluginInfo(
@@ -892,16 +935,12 @@ void MetricsService::StartRecording() {
     // We only need to schedule that run once.
     state_ = INIT_TASK_SCHEDULED;
 
-    // Schedules a task on the file thread for execution of slower
-    // initialization steps (such as plugin list generation) necessary
-    // for sending the initial log.  This avoids blocking the main UI
-    // thread.
-    BrowserThread::PostDelayedTask(
-        BrowserThread::FILE,
+    // Schedules a delayed task for execution of slower initialization steps
+    // (such as plugin list generation) necessary for sending the initial log.
+    MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&MetricsService::InitTaskGetHardwareClass,
-            self_ptr_factory_.GetWeakPtr(),
-            MessageLoop::current()->message_loop_proxy()),
+                   self_ptr_factory_.GetWeakPtr()),
         base::TimeDelta::FromSeconds(kInitializationDelaySeconds));
   }
 }