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 {
+bool StackSamplingConfiguration::GetSyntheticFieldTrial(
+    std::string* trial_name,
+    std::string* group_name) const {
   if (!IsProfilerSupported())
-    return;
+    return false;
 
-  std::string group;
+  *trial_name = "SyntheticStackProfilingConfiguration";
+  *group_name = "";

[sky, 2016/09/29 18:21:36]

Why is this needed? Doesn't the switch statement covert it all?

[Mike Wittman, 2016/09/29 18:27:40]

It does currently. But in the case of future changes I want to explicitly avoid
the possibility of registering a synthetic field trial if the caller happens to
pass a non-empty string to this function.

[sky, 2016/09/29 19:12:49]

Ok, please convert "" to std::string() then.

[Mike Wittman, 2016/09/29 19:25:55]

Done.

   switch (configuration_) {
     case PROFILE_DISABLED:
-      group = "Disabled";
+      *group_name = "Disabled";
       break;
 
     case PROFILE_CONTROL:
-      group = "Control";
+      *group_name = "Control";
       break;
 
     case PROFILE_NO_SAMPLES:
-      group = "NoSamples";
+      *group_name = "NoSamples";
       break;
 
     case PROFILE_5HZ:
-      group = "5Hz";
+      *group_name = "5Hz";
       break;
 
     case PROFILE_10HZ:
-      group = "10Hz";
+      *group_name = "10Hz";
       break;
 
     case PROFILE_100HZ:
-      group = "100Hz";
+      *group_name = "100Hz";
       break;
   }
 
-  ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
-      "SyntheticStackProfilingConfiguration",
-      group);
+  return !group_name->empty();
 }
 
 // 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;
 }