Add process lifetime annotations to stack samples.

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/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/profiler/stack_sampling_profiler.h"
 #include "components/metrics/call_stack_profile_params.h"
 #include "components/metrics/metrics_provider.h"
 
 namespace metrics {
 class ChromeUserMetricsExtension;
 
 // Performs metrics logging for the stack sampling profiler.
 class CallStackProfileMetricsProvider : public MetricsProvider {
  public:
+  // These phases of a process lifetime can be passed as process "phases" to
+  // StackSmaplingProfile::SetProcessPhase(). Be sure to update the translation
+  // constants at the top of the .cc file when this is changed.
+  enum Phases : int {
+    MAIN_LOOP_START,
+    MAIN_NAVIGATION_START,
+    MAIN_NAVIGATION_FINISHED,
+    FIRST_NONEMPTY_PAINT,
+
+    SHUTDOWN_START,
+
+    PHASES_MAX_VALUE
+  };
+
   CallStackProfileMetricsProvider();
   ~CallStackProfileMetricsProvider() override;
 
   // Get a callback for use with StackSamplingProfiler that provides completed
   // profiles to this object. The callback should be immediately passed to the
   // StackSamplingProfiler, and should not be reused between
   // StackSamplingProfilers. This function may be called on any thread.
   static base::StackSamplingProfiler::CompletedCallback GetProfilerCallback(
       const CallStackProfileParams& params);
 
@@ skipping 24 matching lines @@
   // Returns true if reporting of profiles is enabled according to the
   // controlling Finch field trial.
   static bool IsReportingEnabledByFieldTrial();
 
   DISALLOW_COPY_AND_ASSIGN(CallStackProfileMetricsProvider);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_CALL_STACK_PROFILE_METRICS_PROVIDER_H_