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// 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.
#ifndef CHROME_BROWSER_THUMBNAILS_RENDER_WIDGET_SNAPSHOT_TAKER_H_
#define CHROME_BROWSER_THUMBNAILS_RENDER_WIDGET_SNAPSHOT_TAKER_H_
#include <map>
#include "base/basictypes.h"
#include "base/callback_forward.h"
#include "base/gtest_prod_util.h"
#include "base/memory/linked_ptr.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
class SkBitmap;
namespace content {
class RenderWidgetHost;
}
namespace gfx {
class Size;
}
class RenderWidgetSnapshotTaker : public content::NotificationObserver {
public:
typedef base::Callback<void(const SkBitmap&)> SnapshotReadyCallback;
RenderWidgetSnapshotTaker();
virtual ~RenderWidgetSnapshotTaker();
// This registers a callback that can receive the resulting SkBitmap
// from the renderer when it is done rendering it. This is asynchronous,
// and it will also fetch the bitmap even if the tab is hidden.
// In addition, if the renderer has to be invoked, the scaling of
// the thumbnail happens on the rendering thread.
//
// Takes ownership of the callback object.
//
// |page_size| is the size to render the page, and |desired_size| is
// the size to scale the resulting rendered page to (which is done
// efficiently if done in the rendering thread). The resulting image
// will be less then twice the size of the |desired_size| in both
// dimensions, but might not be the exact size requested.
void AskForSnapshot(content::RenderWidgetHost* renderer,
const SnapshotReadyCallback& callback,
gfx::Size page_size,
gfx::Size desired_size);
// Cancel any pending snapshots requested via AskForSnapshot.
void CancelSnapshot(content::RenderWidgetHost* renderer);
private:
FRIEND_TEST_ALL_PREFIXES(RenderWidgetSnapshotTakerTest,
WidgetDidReceivePaintAtSizeAck);
FRIEND_TEST_ALL_PREFIXES(RenderWidgetSnapshotTakerTest,
WidgetDidReceivePaintAtSizeAckFail);
// content::NotificationObserver overrides.
virtual void Observe(int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) OVERRIDE;
// Start or stop monitoring notifications for |renderer| based on the value
// of |monitor|.
void MonitorRenderer(content::RenderWidgetHost* renderer, bool monitor);
void WidgetDidReceivePaintAtSizeAck(content::RenderWidgetHost* widget,
int tag,
const gfx::Size& size);
content::NotificationRegistrar registrar_;
// Map of callback objects by sequence number.
struct AsyncRequestInfo;
typedef std::map<int,
linked_ptr<AsyncRequestInfo> > SnapshotCallbackMap;
SnapshotCallbackMap callback_map_;
// Count of how many outstanding snapshot requests there are for each
// RenderWidgetHost.
std::map<content::RenderWidgetHost*, int> host_monitor_counts_;
DISALLOW_COPY_AND_ASSIGN(RenderWidgetSnapshotTaker);
};
#endif // CHROME_BROWSER_THUMBNAILS_RENDER_WIDGET_SNAPSHOT_TAKER_H_
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