Provide a hint for the idle notification handler.

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 608 matching lines @@
   int64 new_delay_ms = idle_notification_delay_in_ms_ +
                        1000000 / (idle_notification_delay_in_ms_ + 2000);
   if (new_delay_ms >= kLongIdleHandlerDelayMs)
     new_delay_ms = kShortIdleHandlerDelayMs;
 
   if (idle_notifications_to_skip_ > 0) {
     idle_notifications_to_skip_--;
   } else  {
     int cpu_usage = 0;
     Send(new ViewHostMsg_GetCPUUsage(&cpu_usage));
+    // Idle notification hint roughly specifies the expected duration of the
+    // idle pause. We set it proportional to the idle timer delay.
+    int idle_hint = static_cast<int>(new_delay_ms / 10);
     if (cpu_usage < kIdleCPUUsageThresholdInPercents &&
-        v8::V8::IdleNotification()) {
+        v8::V8::IdleNotification(idle_hint)) {
       // V8 finished collecting garbage.
       new_delay_ms = kLongIdleHandlerDelayMs;
     }
   }
   ScheduleIdleHandler(new_delay_ms);
 }
 
 int64 RenderThreadImpl::GetIdleNotificationDelayInMs() const {
   return idle_notification_delay_in_ms_;
 }
@@ skipping 205 matching lines @@
 
 scoped_refptr<base::MessageLoopProxy>
 RenderThreadImpl::GetFileThreadMessageLoopProxy() {
   DCHECK(message_loop() == MessageLoop::current());
   if (!file_thread_.get()) {
     file_thread_.reset(new base::Thread("Renderer::FILE"));
     file_thread_->Start();
   }
   return file_thread_->message_loop_proxy();
 }