[PowerProfiler] Power profiler service keeps running even after devtools frontend has been closed.

content/browser/devtools/devtools_power_handler.cc

 // Copyright 2014 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 "content/browser/devtools/devtools_power_handler.h"
 
 #include "base/bind.h"
 #include "base/values.h"
 #include "content/browser/devtools/devtools_protocol_constants.h"
 #include "content/browser/power_profiler/power_profiler_service.h"
+#include "content/public/browser/devtools_manager.h"
 
 namespace content {
 
-DevToolsPowerHandler::DevToolsPowerHandler() {
+DevToolsPowerHandler::DevToolsPowerHandler(
+    DevToolsAgentHost* devtools_agent_host)
+    : devtools_agent_host_(devtools_agent_host),
+      devtools_callback_(
+          base::Bind(&DevToolsPowerHandler::OnDevToolsStateChanged,
+                     base::Unretained(this))) {
   RegisterCommandHandler(devtools::Power::start::kName,
                          base::Bind(&DevToolsPowerHandler::OnStart,
                                     base::Unretained(this)));
   RegisterCommandHandler(devtools::Power::end::kName,
                          base::Bind(&DevToolsPowerHandler::OnEnd,
                                     base::Unretained(this)));
   RegisterCommandHandler(devtools::Power::canProfilePower::kName,
                          base::Bind(&DevToolsPowerHandler::OnCanProfilePower,
                                     base::Unretained(this)));
+  content::DevToolsManager::GetInstance()->AddAgentStateCallback(
+      devtools_callback_);
 }
 
 DevToolsPowerHandler::~DevToolsPowerHandler() {
   PowerProfilerService::GetInstance()->RemoveObserver(this);
+  content::DevToolsManager::GetInstance()->RemoveAgentStateCallback(
+      devtools_callback_);
 }
 
 void DevToolsPowerHandler::OnPowerEvent(const PowerEventVector& events) {
   base::DictionaryValue* params = new base::DictionaryValue();
   base::ListValue* event_list = new base::ListValue();
 
   std::vector<PowerEvent>::const_iterator iter;
   for (iter = events.begin(); iter != events.end(); ++iter) {
     base::DictionaryValue* event_body = new base::DictionaryValue();
 
@@ skipping 35 matching lines @@
 scoped_refptr<DevToolsProtocol::Response>
 DevToolsPowerHandler::OnCanProfilePower(
     scoped_refptr<DevToolsProtocol::Command> command) {
   base::DictionaryValue* result = new base::DictionaryValue();
   result->SetBoolean(devtools::kResult,
                      PowerProfilerService::GetInstance()->IsAvailable());
 
   return command->SuccessResponse(result);
 }
 
+void DevToolsPowerHandler::OnDevToolsStateChanged(
+    content::DevToolsAgentHost* agent_host,
+    bool attached) {
+  if (!attached && agent_host == devtools_agent_host_) {
+    PowerProfilerService::GetInstance()->RemoveObserver(this);
+  }
+}
+
 }  // namespace content