DevTools: use explicit IPC messages for enabling/disabling tracing instead of intercepting protocol…

content/browser/devtools/render_view_devtools_agent_host.cc

Index: content/browser/devtools/render_view_devtools_agent_host.cc
diff --git a/content/browser/devtools/render_view_devtools_agent_host.cc b/content/browser/devtools/render_view_devtools_agent_host.cc
index 12a05d55b746b29c5a929e1c78d99b299d944bfb..a858ff8382e12da033fddc9b0d196844e5d1dd8b 100644
--- a/content/browser/devtools/render_view_devtools_agent_host.cc
+++ b/content/browser/devtools/render_view_devtools_agent_host.cc
@@ -441,6 +441,8 @@ bool RenderViewDevToolsAgentHost::DispatchIPCMessage(
                         OnDispatchOnInspectorFrontend)
     IPC_MESSAGE_HANDLER(DevToolsHostMsg_SaveAgentRuntimeState,
                         OnSaveAgentRuntimeState)
+    IPC_MESSAGE_HANDLER(DevToolsHostMsg_EnableTracing, OnEnableTracing)
+    IPC_MESSAGE_HANDLER(DevToolsHostMsg_DisableTracing, OnDisableTracing)
     IPC_MESSAGE_HANDLER_GENERIC(ViewHostMsg_SwapCompositorFrame,
                                 handled = false; OnSwapCompositorFrame(msg))
     IPC_MESSAGE_UNHANDLED(handled = false)
@@ -474,14 +476,16 @@ void RenderViewDevToolsAgentHost::OnDispatchOnInspectorFrontend(
     const std::string& message) {
   if (!render_view_host_)
     return;
+  SendMessageToClient(message);
+}
 
-  scoped_refptr<DevToolsProtocol::Notification> notification =
-      DevToolsProtocol::ParseNotification(message);
+void RenderViewDevToolsAgentHost::OnEnableTracing(
+    const std::string& category_filter) {
+  tracing_handler_->EnableTracing(category_filter);
+}
 
-  if (notification.get()) {
-    tracing_handler_->HandleNotification(notification);
-  }
-  SendMessageToClient(message);
+void RenderViewDevToolsAgentHost::OnDisableTracing() {
+  tracing_handler_->DisableTracing();
 }
 
 }  // namespace content