Stack sampling profiler: move configuration to chrome/common

chrome/common/stack_sampling_configuration.cc

 // 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.
 
-#include "chrome/browser/stack_sampling_configuration.h"
+#include "chrome/common/stack_sampling_configuration.h"
 
 #include "base/rand_util.h"
-#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/common/channel_info.h"
 #include "components/version_info/version_info.h"
 
 namespace {
 
 // The profiler is currently only implemented for Windows x64, and only runs on
 // trunk, canary, and dev.
 bool IsProfilerSupported() {
 #if !defined(_WIN64)
   return false;
@@ skipping 50 matching lines @@
       break;
   }
   return params;
 }
 
 bool StackSamplingConfiguration::IsProfilerEnabled() const {
   return (configuration_ != PROFILE_DISABLED &&
           configuration_ != PROFILE_CONTROL);
 }
 
-void StackSamplingConfiguration::RegisterSyntheticFieldTrial() const {
+void StackSamplingConfiguration::RegisterSyntheticFieldTrial(
+    const RegisterSyntheticFieldTrialFunction& register_field_trial) const {

[sky, 2016/09/28 20:34:14]

How come you need a callback here? Could this instead return a struct with the
two strings?

[Mike Wittman, 2016/09/28 21:51:27]

The callback is not strictly necessary, but it allows the decisions about both
the field trial parameters and whether to register the field trial to be
encapsulated within the configuration class.

   if (!IsProfilerSupported())
     return;
 
   std::string group;
   switch (configuration_) {
     case PROFILE_DISABLED:
       group = "Disabled";
       break;
 
     case PROFILE_CONTROL:
@@ skipping 10 matching lines @@
 
     case PROFILE_10HZ:
       group = "10Hz";
       break;
 
     case PROFILE_100HZ:
       group = "100Hz";
       break;
   }
 
-  ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
-      "SyntheticStackProfilingConfiguration",
-      group);
+  register_field_trial.Run("SyntheticStackProfilingConfiguration", group);
 }
 
 // static
 StackSamplingConfiguration::ProfileConfiguration
 StackSamplingConfiguration::GenerateConfiguration() {
   if (!IsProfilerSupported())
     return PROFILE_DISABLED;
 
   // Enable the profiler in the intended ultimate production configuration for
   // development/waterfall builds.
@@ skipping 27 matching lines @@
           chosen < cumulative_weight + variation.weight) {
         return variation.config;
       }
       cumulative_weight += variation.weight;
     }
     NOTREACHED();
   }
 
   return PROFILE_DISABLED;
 }