Plugin Power Saver: Make PepperPluginInstanceThrottler interface public.

content/public/renderer/plugin_instance_throttler.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_THROTTLER_H_
-#define CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_THROTTLER_H_
+#ifndef CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_
+#define CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_
 
-#include "base/callback.h"
 #include "base/macros.h"
-#include "base/memory/weak_ptr.h"
+#include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
-#include "content/public/renderer/render_frame.h"
-#include "ppapi/shared_impl/ppb_view_shared.h"
-#include "third_party/WebKit/public/platform/WebRect.h"
-
-namespace blink {
-class WebInputEvent;
-}
 
 class GURL;
-class SkBitmap;
 
 namespace content {
 
-// Manages the Plugin Power Saver feature for a single Pepper plugin instance.
+class RenderFrame;
+
+// Plugin instances are "peripheral" if they are heuristically determined to be
+// not "essential" to the web page content. See RenderFrame comments for

[Lei Zhang, 2015/01/16 01:09:58]

Which "RenderFrame comments" are we referring to?

[tommycli, 2015/01/16 01:26:10]

Done.

+// details on these heuristics.
+enum PluginPowerSaverMode {
+  // Plugin content is main content, and therefore never throttled.
+  POWER_SAVER_MODE_ESSENTIAL = 0,
+  // Plugin content is peripheral, but throttling is disabled.
+  POWER_SAVER_MODE_PERIPHERAL_UNTHROTTLED = 1,
+  // Plugin content is peripheral, and throttling is enabled.
+  POWER_SAVER_MODE_PERIPHERAL_THROTTLED = 2
+};
+
+// This class manages the metric collection, throttling, and unthrottling of a
+// single peripheral plugin instance. If the Power Saver feature is disabled,
+// the plugin instance will never actually be throttled, but still collects
+// user interaction metrics.
 //
-// A plugin must meet certain criteria in order to be throttled (e.g. it must
-// be a Flash plugin, it must meet certain size criteria, etc.). The process
-// for throttling a plugin is as follows:
+// The process for throttling a plugin is as follows:
 // 1) Attempt to find a representative keyframe to display as a placeholder for
 //    the plugin.
 // 2) a) If a representative keyframe is found, throttle the plugin at that
 //       keyframe.
 //    b) If a representative keyframe is not found, throttle the plugin after a
 //       certain period of time.
 //
 // The plugin will then be unthrottled by receiving a mouse click from the user.
 //
 // To choose a representative keyframe, we first wait for a certain number of
 // "interesting" frames to be displayed by the plugin. A frame is called
 // interesting if it meets some heuristic. After we have seen a certain number
 // of interesting frames, we throttle the plugin and use that frame as the
 // representative keyframe.
-class CONTENT_EXPORT PepperPluginInstanceThrottler {
+class CONTENT_EXPORT PluginInstanceThrottler {
  public:
   // How the throttled power saver is unthrottled, if ever.
   // These numeric values are used in UMA logs; do not change them.
   enum PowerSaverUnthrottleMethod {
     UNTHROTTLE_METHOD_NEVER = 0,
     UNTHROTTLE_METHOD_BY_CLICK = 1,
     UNTHROTTLE_METHOD_BY_WHITELIST = 2,
     UNTHROTTLE_METHOD_BY_AUDIO = 3,
     UNTHROTTLE_METHOD_NUM_ITEMS
   };
 
-  PepperPluginInstanceThrottler(
+  class Observer {
+   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 blink::WebRect& bounds,
-      bool is_flash_plugin,
       const GURL& plugin_url,
-      RenderFrame::PluginPowerSaverMode power_saver_mode,
-      const base::Closure& throttle_change_callback);
+      PluginPowerSaverMode power_saver_mode);
 
-  virtual ~PepperPluginInstanceThrottler();
+  virtual ~PluginInstanceThrottler() {}
 
-  bool needs_representative_keyframe() const {
-    return needs_representative_keyframe_;
-  }
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
 
-  bool power_saver_enabled() const {
-    return power_saver_enabled_;
-  }
+  virtual bool IsThrottled() const = 0;
 
-  // Called when the plugin flushes it's graphics context. Supplies the
-  // throttler with a candidate to use as the representative keyframe.
-  void OnImageFlush(const SkBitmap* bitmap);
+  // Marks the plugin as essential. Unthrottles the plugin if already throttled.
+  virtual void MarkPluginEssential(PowerSaverUnthrottleMethod method) = 0;
 
-  bool is_throttled() const { return plugin_throttled_; }
-
-  // Returns true if |event| was handled and shouldn't be further processed.
-  bool ConsumeInputEvent(const blink::WebInputEvent& event);
-
-  // Disables Power Saver and unthrottles the plugin if already throttled.
-  void DisablePowerSaver(PowerSaverUnthrottleMethod method);
+ protected:
+  PluginInstanceThrottler() {}
 
  private:
-  friend class PepperPluginInstanceThrottlerTest;
-
-  void SetPluginThrottled(bool throttled);
-
-  // Plugin's bounds in view space.
-  blink::WebRect bounds_;
-
-  // Called when the throttle state changes.
-  base::Closure throttle_change_callback_;
-
-  bool is_flash_plugin_;
-
-  // True if throttler is still waiting to find a representative keyframe.
-  bool needs_representative_keyframe_;
-
-  // Number of consecutive interesting frames we've encountered.
-  int consecutive_interesting_frames_;
-
-  // Set to true first time plugin is clicked. Used to collect metrics.
-  bool has_been_clicked_;
-
-  // Indicates whether this plugin may be throttled to reduce power consumption.
-  // |power_saver_enabled_| implies |is_peripheral_content_|.
-  bool power_saver_enabled_;
-
-  // Indicates whether this plugin was found to be peripheral content.
-  // This is separately tracked from |power_saver_enabled_| to collect UMAs.
-  // Always true if |power_saver_enabled_| is true.
-  bool is_peripheral_content_;
-
-  // Indicates if the plugin is currently throttled.
-  bool plugin_throttled_;
-
-  base::WeakPtrFactory<PepperPluginInstanceThrottler> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(PepperPluginInstanceThrottler);
+  DISALLOW_COPY_AND_ASSIGN(PluginInstanceThrottler);
 };
 }
 
-#endif  // CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_THROTTLER_H_
+#endif  // CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_