Plugin Power Saver: Make Unthrottle metric collection more consistent

content/public/renderer/plugin_instance_throttler.h

 // Copyright 2015 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.
 
 #ifndef CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_
 #define CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
@@ skipping 52 matching lines @@
    public:
     virtual void OnThrottleStateChange() = 0;
   };
 
   // Returns a nullptr if no throttler needed based on |power_saver_mode|.
   static scoped_ptr<PluginInstanceThrottler> Get(
       RenderFrame* frame,
       const GURL& plugin_url,
       PluginPowerSaverMode power_saver_mode);
 
+  static void RecordUnthrottleMethodMetric(PowerSaverUnthrottleMethod method);
+
   virtual ~PluginInstanceThrottler() {}
 
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
   virtual bool IsThrottled() const = 0;
 
   // Marks the plugin as essential. Unthrottles the plugin if already throttled.
   virtual void MarkPluginEssential(PowerSaverUnthrottleMethod method) = 0;
 
  protected:
   PluginInstanceThrottler() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PluginInstanceThrottler);
 };
 }
 
 #endif  // CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_