[DevTools] Tracing handler keeps running even after devtools frontend has been closed.

content/browser/devtools/devtools_tracing_handler.cc

Index: content/browser/devtools/devtools_tracing_handler.cc
diff --git a/content/browser/devtools/devtools_tracing_handler.cc b/content/browser/devtools/devtools_tracing_handler.cc
index b20c146eb87b28c8d191b555d484e4d1d188c0e9..19ec9769d48f65c9b2ad34e463298866743dd4e5 100644
--- a/content/browser/devtools/devtools_tracing_handler.cc
+++ b/content/browser/devtools/devtools_tracing_handler.cc
@@ -200,12 +200,21 @@ void DevToolsTracingHandler::OnBufferUsage(float usage) {
 scoped_refptr<DevToolsProtocol::Response>
 DevToolsTracingHandler::OnEnd(
     scoped_refptr<DevToolsProtocol::Command> command) {
-  buffer_usage_poll_timer_.reset();
-  TracingController::GetInstance()->DisableRecording(
-      base::FilePath(),
+  DisableRecording(
       base::Bind(&DevToolsTracingHandler::BeginReadingRecordingResult,
                  weak_factory_.GetWeakPtr()));
   return command->SuccessResponse(NULL);
 }
 
+void DevToolsTracingHandler::DisableRecording(
+    const TracingController::TracingFileResultCallback& callback) {
+  buffer_usage_poll_timer_.reset();
+  TracingController::GetInstance()->DisableRecording(base::FilePath(),
+                                                     callback);
+}
+
+void DevToolsTracingHandler::OnClientDetached() {
+    DisableRecording();
+}
+
 }  // namespace content