[Extensions] Add renderer-side logic to short circuit activity logging

extensions/renderer/scripts_run_info.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/scripts_run_info.h"
 
 #include "base/metrics/histogram.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_thread.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/renderer/script_context.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 
 namespace extensions {
 
 ScriptsRunInfo::ScriptsRunInfo(content::RenderFrame* render_frame,
                                UserScript::RunLocation location)
     : num_css(0u),
       num_js(0u),
       num_blocking_js(0u),
       routing_id_(render_frame->GetRoutingID()),
       run_location_(location),
       frame_url_(ScriptContext::GetDataSourceURLForFrame(
           render_frame->GetWebFrame())) {
 }
 
 ScriptsRunInfo::~ScriptsRunInfo() {
 }
 
-void ScriptsRunInfo::LogRun() {
+void ScriptsRunInfo::LogRun(bool send_script_activity) {
   // Notify the browser if any extensions are now executing scripts.
-  if (!executing_scripts.empty()) {
+  if (!executing_scripts.empty() && send_script_activity) {
     content::RenderThread::Get()->Send(
         new ExtensionHostMsg_ContentScriptsExecuting(
             routing_id_, executing_scripts, frame_url_));
   }
 
   switch (run_location_) {
     case UserScript::DOCUMENT_START:
       UMA_HISTOGRAM_COUNTS_100("Extensions.InjectStart_CssCount", num_css);
       UMA_HISTOGRAM_COUNTS_100("Extensions.InjectStart_ScriptCount", num_js);
       if (num_blocking_js) {
@@ skipping 25 matching lines @@
     case UserScript::BROWSER_DRIVEN:
       // TODO(rdevlin.cronin): Add histograms.
       break;
     case UserScript::UNDEFINED:
     case UserScript::RUN_LOCATION_LAST:
       NOTREACHED();
   }
 }
 
 }  // namespace extensions