Provide a hint for the idle notification handler.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 6dd026c31e925f139a192013df44f1db078e2704..d5fc6d79a56993d2d9e96c043ac274c59dafd2a3 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -626,8 +626,11 @@ void RenderThreadImpl::IdleHandlerInForegroundTab() {
   } 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;
     }