Set IdleHandler timer on background threads a minimum of 30s in the future after initial run.

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 1034 matching lines @@
   }
 
   // Schedule next invocation. When the tab is originally hidden, an invocation
   // is scheduled for kInitialIdleHandlerDelayMs in
   // RenderThreadImpl::WidgetHidden in order to race to a minimal heap.
   // After that, idle calls can be much less frequent, so run at a maximum of
   // once every kLongIdleHandlerDelayMs.
   // Dampen the delay using the algorithm (if delay is in seconds):
   //    delay = delay + 1 / (delay + 2)
   // Using floor(delay) has a dampening effect such as:
-  //    30s, 30, 30, 31, 31, 31, 31, 32, 32, ...
+  //    30s repeated > 30 times, 31s repeated > 30 times, 32s...
   // If the delay is in milliseconds, the above formula is equivalent to:
   //    delay_ms / 1000 = delay_ms / 1000 + 1 / (delay_ms / 1000 + 2)
   // which is equivalent to
   //    delay_ms = delay_ms + 1000*1000 / (delay_ms + 2000).
   if (continue_timer) {
     ScheduleIdleHandler(
         std::max(kLongIdleHandlerDelayMs,
                  idle_notification_delay_in_ms_ +
                  1000000 / (idle_notification_delay_in_ms_ + 2000)));
 
@@ skipping 572 matching lines @@
   hidden_widget_count_--;
 
   if (!GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden()) {
     return;
   }
 
   ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 }
 
 }  // namespace content