Make tracing based Timeline stop after reloading inspected page

This change fixes the following problem:
1. Run browser with remote debugging enabled (--remote-debugging-port=9222)
2. Open remote debugging front-end in the same browser (localhost:9222)
3. Inspect that front-end using built-in DevTools.
4. Go to Timeline and press Ctrl+R

Result:
Timeline recording starts automatically and never stops after reload.

With this patch:
It will stop recoding after reload.

BUG=None

Review URL: https://codereview.chromium.org/409073003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284706 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/devtools/devtools_tracing_handler.cc

@@ -48,7 +48,7 @@ void ReadFile(
 
 DevToolsTracingHandler::DevToolsTracingHandler(
     DevToolsTracingHandler::Target target)
-    : weak_factory_(this), target_(target) {
+    : weak_factory_(this), target_(target), is_recording_(false) {
   RegisterCommandHandler(devtools::Tracing::start::kName,
                          base::Bind(&DevToolsTracingHandler::OnStart,
                                     base::Unretained(this)));
@@ -138,6 +138,7 @@ TracingController::Options DevToolsTracingHandler::TraceOptionsFromString(
 scoped_refptr<DevToolsProtocol::Response>
 DevToolsTracingHandler::OnStart(
     scoped_refptr<DevToolsProtocol::Command> command) {
+  is_recording_ = true;
   std::string categories;
   base::DictionaryValue* params = command->params();
   if (params)
@@ -211,12 +212,14 @@ DevToolsTracingHandler::OnEnd(
 
 void DevToolsTracingHandler::DisableRecording(
     const TracingController::TracingFileResultCallback& callback) {
+  is_recording_ = false;
   buffer_usage_poll_timer_.reset();
   TracingController::GetInstance()->DisableRecording(base::FilePath(),
                                                      callback);
 }
 
 void DevToolsTracingHandler::OnClientDetached() {
+  if (is_recording_)
     DisableRecording();
 }
 

content/browser/devtools/devtools_tracing_handler.h

@@ -55,6 +55,7 @@ class DevToolsTracingHandler : public DevToolsProtocol::Handler {
   base::WeakPtrFactory<DevToolsTracingHandler> weak_factory_;
   scoped_ptr<base::Timer> buffer_usage_poll_timer_;
   Target target_;
+  bool is_recording_;
   DISALLOW_COPY_AND_ASSIGN(DevToolsTracingHandler);
 };