Enable startup profiling by Win x64 stack sampling profiler

components/metrics/call_stack_profile_metrics_provider.h

Index: components/metrics/call_stack_profile_metrics_provider.h
diff --git a/components/metrics/call_stack_profile_metrics_provider.h b/components/metrics/call_stack_profile_metrics_provider.h
index a2bb0f85a31bd8de9d0c53ad4d138ed1940aed4a..0de3017371eb9b889ea46c333ea258575acdc955 100644
--- a/components/metrics/call_stack_profile_metrics_provider.h
+++ b/components/metrics/call_stack_profile_metrics_provider.h
@@ -7,7 +7,9 @@
 
 #include <vector>
 
+#include "base/memory/weak_ptr.h"
 #include "base/profiler/stack_sampling_profiler.h"
+#include "base/synchronization/lock.h"
 #include "components/metrics/metrics_provider.h"
 
 namespace metrics {
@@ -20,6 +22,8 @@ class CallStackProfileMetricsProvider : public MetricsProvider {
   ~CallStackProfileMetricsProvider() override;
 
   // MetricsProvider:
+  void OnRecordingEnabled() override;
+  void OnRecordingDisabled() override;
   void ProvideGeneralMetrics(ChromeUserMetricsExtension* uma_proto) override;
 
   // Uses |profiles| as the source data for the next invocation of
@@ -28,8 +32,23 @@ class CallStackProfileMetricsProvider : public MetricsProvider {
   void SetSourceProfilesForTesting(
       const std::vector<base::StackSamplingProfiler::Profile>& profiles);
 
+  // Finch field trial and group for reporting profiles.
+  static const char kFieldTrialName[];
+  static const char kReportProfilesGroupName[];

[Ilya Sherman, 2015/03/24 04:02:03]

nit: If these are only used for tests, please mark them as protected, and expose
them for tests in a test-specific subclass.

[Mike Wittman, 2015/03/24 18:37:39]

Done.

+
  private:
-  std::vector<base::StackSamplingProfiler::Profile> source_profiles_for_test_;
+  // These functions will be called on a separate thread.
+  void ReceiveCompletedProfiles(
+      const std::vector<base::StackSamplingProfiler::Profile>& profiles);
+  static void IgnoreCompletedProfiles(
+      const std::vector<base::StackSamplingProfiler::Profile>& profiles);

[Ilya Sherman, 2015/03/24 04:02:03]

Can this be moved to an anonymous namespace in the implementation file?

[Mike Wittman, 2015/03/24 18:37:39]

Done.

+
+  // Pending profiles are updated from the profiler on a separate thread, so
+  // must be guarded by a lock.
+  base::Lock pending_profiles_lock_;
+  std::vector<base::StackSamplingProfiler::Profile> pending_profiles_;

[Ilya Sherman, 2015/03/24 04:02:03]

Could you please instead post a task to the thread that the class lives on?  I
don't think metrics providers have any thread-safety guarantees...

[Mike Wittman, 2015/03/24 18:37:39]

Done.

+
+  base::WeakPtrFactory<CallStackProfileMetricsProvider> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CallStackProfileMetricsProvider);
 };