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// 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"
namespace blink {
struct WebPluginParams;
}
class GURL;
class SkBitmap;
namespace content {
// 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.
//
// 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 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
};
class Observer {
public:
// Guaranteed to be called before the throttle is engaged.
virtual void OnKeyframeExtracted(const SkBitmap* bitmap) {}
virtual void OnThrottleStateChange() {}
// Called when the plugin should be hidden due to a placeholder.
virtual void OnHiddenForPlaceholder(bool hidden) {}
virtual void OnThrottlerDestroyed() {}
};
static scoped_ptr<PluginInstanceThrottler> Create(bool power_saver_enabled);
static void RecordUnthrottleMethodMetric(PowerSaverUnthrottleMethod method);
virtual ~PluginInstanceThrottler() {}
virtual void AddObserver(Observer* observer) = 0;
virtual void RemoveObserver(Observer* observer) = 0;
virtual bool IsThrottled() const = 0;
virtual bool IsHiddenForPlaceholder() const = 0;
// Marks the plugin as essential. Unthrottles the plugin if already throttled.
virtual void MarkPluginEssential(PowerSaverUnthrottleMethod method) = 0;
// Called by the placeholder when the plugin should temporarily be hidden.
virtual void SetHiddenForPlaceholder(bool hidden) = 0;
protected:
PluginInstanceThrottler() {}
private:
DISALLOW_COPY_AND_ASSIGN(PluginInstanceThrottler);
};
}
#endif // CONTENT_PUBLIC_RENDERER_PLUGIN_INSTANCE_THROTTLER_H_
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