Enable startup profiling by Win x64 stack sampling profiler

components/metrics/call_stack_profile_metrics_provider.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_METRICS_CALL_STACK_PROFILE_METRICS_PROVIDER_H_
 #define COMPONENTS_METRICS_CALL_STACK_PROFILE_METRICS_PROVIDER_H_
 
 #include <vector>
 
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/profiler/stack_sampling_profiler.h"
+#include "base/synchronization/lock.h"

[Ilya Sherman, 2015/03/24 21:07:55]

nit: No longer needed.

[Mike Wittman, 2015/03/24 22:40:59]

Done.

 #include "components/metrics/metrics_provider.h"
 
 namespace metrics {
 class ChromeUserMetricsExtension;
 
 // Performs metrics logging for the stack sampling profiler.
 class CallStackProfileMetricsProvider : public MetricsProvider {
  public:
   CallStackProfileMetricsProvider();
   ~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
   // ProvideGeneralMetrics, rather than sourcing them from the
   // StackSamplingProfiler.
   void SetSourceProfilesForTesting(
       const std::vector<base::StackSamplingProfiler::Profile>& profiles);
 
+ protected:
+  // Finch field trial and group for reporting profiles. Provided here for test
+  // use.
+  static const char kFieldTrialName[];
+  static const char kReportProfilesGroupName[];

[Ilya Sherman, 2015/03/24 21:07:55]

Optional: Actually, an easier option for testing might be to expose a protected
method "virtual bool IsEnabled()" (or a more detailed name, if you prefer).  The
production implementation could test the field trial state, whereas the test
could just return true or false as desired.  That way, the test doesn't need to
worry about Finch integration at all.

[Mike Wittman, 2015/03/24 22:40:59]

Hmm, I'm not enthusiastic about the impact of that approach on the interface.
Providing a method to determine the enable state implies that state varies
per-object in the implementation, when in fact it's global.

+
  private:
-  std::vector<base::StackSamplingProfiler::Profile> source_profiles_for_test_;
+  // Returns true if reporting of profiles is enabled according to the
+  // controlling Finch field trial.
+  static bool IsSamplingProfilingReportingEnabled();
+
+  // Invoked by the profiler on another thread.
+  static void ReceiveCompletedProfiles(
+      scoped_refptr<base::MessageLoopProxy> message_loop,

[Ilya Sherman, 2015/03/24 21:07:55]

nit: Forward-declare the MessageLoopProxy class?

[Mike Wittman, 2015/03/24 22:40:59]

Done.

+      base::WeakPtr<CallStackProfileMetricsProvider> provider,
+      const std::vector<base::StackSamplingProfiler::Profile>& profiles);
+  void AppendCompletedProfiles(
+      const std::vector<base::StackSamplingProfiler::Profile>& profiles);
+
+  std::vector<base::StackSamplingProfiler::Profile> pending_profiles_;
+
+  base::WeakPtrFactory<CallStackProfileMetricsProvider> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CallStackProfileMetricsProvider);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_CALL_STACK_PROFILE_METRICS_PROVIDER_H_