Plugin Power Saver: Make PepperPluginInstanceThrottler interface public.

content/renderer/pepper/plugin_instance_throttler_impl.h

+// Copyright 2014 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_PLUGIN_INSTANCE_THROTTLER_IMPL_H_
+#define CONTENT_RENDERER_PEPPER_PLUGIN_INSTANCE_THROTTLER_IMPL_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "content/common/content_export.h"
+#include "content/public/renderer/plugin_instance_throttler.h"
+#include "ppapi/shared_impl/ppb_view_shared.h"
+#include "third_party/WebKit/public/platform/WebRect.h"
+
+namespace blink {
+class WebInputEvent;
+}
+
+class SkBitmap;
+
+namespace content {
+
+class CONTENT_EXPORT PluginInstanceThrottlerImpl

[Lei Zhang, 2015/01/16 00:19:32]

You may want to define "essential" and "peripheral", and mention this class only
deals with peripheral plugins.

[tommycli, 2015/01/16 00:51:56]

Done. I added to the comments in the plugin_instance_throttler.h file.

+    : public PluginInstanceThrottler {
+ public:
+  PluginInstanceThrottlerImpl(RenderFrame* frame,
+                              const GURL& plugin_url,
+                              bool power_saver_enabled);
+
+  ~PluginInstanceThrottlerImpl() override;
+
+  // PluginInstanceThrottler implementation:
+  void AddObserver(Observer* observer) override;
+  void RemoveObserver(Observer* observer) override;
+  bool IsThrottled() const override;
+  void MarkPluginEssential(PowerSaverUnthrottleMethod method) override;
+
+  bool needs_representative_keyframe() const {
+    return state_ == POWER_SAVER_ENABLED_AWAITING_KEYFRAME;
+  }
+
+  bool power_saver_enabled() const {
+    return state_ == POWER_SAVER_ENABLED_AWAITING_KEYFRAME ||
+           state_ == POWER_SAVER_ENABLED_PLUGIN_THROTTLED;
+  }
+
+  // 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);
+
+  // Returns true if |event| was handled and shouldn't be further processed.
+  bool ConsumeInputEvent(const blink::WebInputEvent& event);
+
+ private:
+  friend class PluginInstanceThrottlerImplTest;
+
+  enum State {
+    // Initial state if Power Saver is disabled. We are just collecting metrics.
+    POWER_SAVER_DISABLED,
+    // Initial state if Power Saver is enabled. Waiting for a keyframe.
+    POWER_SAVER_ENABLED_AWAITING_KEYFRAME,
+    // We've chosen a keyframe and the plug-in is throttled.
+    POWER_SAVER_ENABLED_PLUGIN_THROTTLED,
+    // Plugin instance is no longer considered peripheral. This can happen from
+    // a user click, whitelisting, or some other reason. We can end up in this
+    // state regardless of whether power saver is enabled.
+    PLUGIN_INSTANCE_MARKED_ESSENTIAL
+  };
+
+  void EngageThrottle();
+
+  State state_;
+
+  // Number of consecutive interesting frames we've encountered.
+  int consecutive_interesting_frames_;
+
+  ObserverList<Observer> observer_list_;
+
+  base::WeakPtrFactory<PluginInstanceThrottlerImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PluginInstanceThrottlerImpl);
+};
+}
+
+#endif  // CONTENT_RENDERER_PEPPER_PLUGIN_INSTANCE_THROTTLER_IMPL_H_