[Extensions] Add perf metrics for StartRequest()/HandleResponse()

extensions/renderer/request_sender.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 "extensions/renderer/request_sender.h"
 
+#include "base/metrics/histogram_macros.h"
+#include "base/timer/elapsed_timer.h"
 #include "base/values.h"
 #include "content/public/renderer/render_frame.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/renderer/script_context.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebScopedUserGesture.h"
 #include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
 #include "third_party/WebKit/public/web/WebUserGestureToken.h"
 
@@ skipping 42 matching lines @@
   linked_ptr<PendingRequest> result = i->second;
   pending_requests_.erase(i);
   return result;
 }
 
 int RequestSender::GetNextRequestId() const {
   static int next_request_id = 0;
   return next_request_id++;
 }
 
-void RequestSender::StartRequest(Source* source,
+bool RequestSender::StartRequest(Source* source,
                                  const std::string& name,
                                  int request_id,
                                  bool has_callback,
                                  bool for_io_thread,
                                  base::ListValue* value_args) {
   ScriptContext* context = source->GetContext();
   if (!context)
-    return;
+    return false;
 
   bool for_service_worker =
       context->context_type() == Feature::SERVICE_WORKER_CONTEXT;
   // Get the current RenderFrame so that we can send a routed IPC message from
   // the correct source.
   // Note that |render_frame| would be nullptr for Service Workers. Service
   // Workers use control IPC instead.
   content::RenderFrame* render_frame = context->GetRenderFrame();
   if (!for_service_worker && !render_frame) {
     // It is important to early exit here for non Service Worker contexts so
     // that we do not create orphaned PendingRequests below.
-    return;
+    return false;
   }
 
   // TODO(koz): See if we can make this a CHECK.
   if (!context->HasAccessOrThrowError(name))
-    return;
+    return false;
 
   GURL source_url;
   if (blink::WebLocalFrame* webframe = context->web_frame())
     source_url = webframe->document().url();
 
   InsertRequest(request_id, new PendingRequest(name, source,
       blink::WebUserGestureIndicator::currentUserGestureToken()));
 
   ExtensionHostMsg_Request_Params params;
   params.name = name;
   params.arguments.Swap(value_args);
   params.extension_id = context->GetExtensionID();
   params.source_url = source_url;
   params.source_tab_id = source_tab_id_;
   params.request_id = request_id;
   params.has_callback = has_callback;
   params.user_gesture =
       blink::WebUserGestureIndicator::isProcessingUserGesture();
 
   // Set Service Worker specific params to default values.
   params.worker_thread_id = -1;
   params.embedded_worker_id = -1;
 
   SendRequest(render_frame, for_io_thread, params);
+  return true;
 }
 
 void RequestSender::SendRequest(content::RenderFrame* render_frame,
                                 bool for_io_thread,
                                 ExtensionHostMsg_Request_Params& params) {
   if (for_io_thread) {
     render_frame->Send(new ExtensionHostMsg_RequestForIOThread(
         render_frame->GetRoutingID(), params));
   } else {
     render_frame->Send(
         new ExtensionHostMsg_Request(render_frame->GetRoutingID(), params));
   }
 }
 
 void RequestSender::HandleResponse(int request_id,
                                    bool success,
                                    const base::ListValue& response,
                                    const std::string& error) {
+  base::ElapsedTimer timer;
   linked_ptr<PendingRequest> request = RemoveRequest(request_id);
 
   if (!request.get()) {
     // This can happen if a context is destroyed while a request is in flight.
     return;
   }
 
+  // TODO(devlin): Would it be useful to partition this data based on
+  // extension function once we have a suitable baseline? crbug.com/608561.
   blink::WebScopedUserGesture gesture(request->token);
   request->source->OnResponseReceived(
       request->name, request_id, success, response, error);
+  UMA_HISTOGRAM_TIMES("Extensions.Functions.HandleResponseElapsedTime",
+                      timer.Elapsed());
 }
 
 void RequestSender::InvalidateSource(Source* source) {
   for (PendingRequestMap::iterator it = pending_requests_.begin();
        it != pending_requests_.end();) {
     if (it->second->source == source)
       pending_requests_.erase(it++);
     else
       ++it;
   }
 }
 
 }  // namespace extensions