Add support for begin frame scheduling and direct rendering when GPU compositing is disabled (issue #1368).

- Always set the browser process VSync rate (frame rate) to CefSettings.windowless_frame_rate.
- When the `enable-begin-frame-scheduling` command-line flag is specified the VSync rate for all processes will be synchronized to CefSettings.windowless_frame_rate. This flag cannot be used in combination with windowed rendering.
- When the `disable-gpu` and `disable-gpu-compositing` command-line flags are specified the CefRenderHandler::OnPaint method will be called directly from the compositor instead of requiring an additional copy for each frame.
- CefRenderHandler::OnPopupSize now passes view coordinates instead of (potentially scaled) pixel coordinates.
- Add OSR unit tests for 2x (HiDPI) pixel scaling.
- Improve CefRenderHandler documentation.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@1960 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser/software_output_device_osr.h

@@ -0,0 +1,56 @@
+// Copyright (c) 2014 The Chromium Embedded Framework Authors.
+// Portions copyright (c) 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 CEF_LIBCEF_BROWSER_SOFTWARE_OUTPUT_DEVICE_OSR_H_
+#define CEF_LIBCEF_BROWSER_SOFTWARE_OUTPUT_DEVICE_OSR_H_
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/output/software_output_device.h"
+
+namespace ui {
+class Compositor;
+}
+
+// Device implementation for direct software rendering via DelegatedFrameHost.
+// All Rect/Size values are in pixels.
+class CefSoftwareOutputDeviceOSR : public cc::SoftwareOutputDevice {
+ public:
+  typedef base::Callback<void(const gfx::Rect&,int,int,void*)>
+      OnPaintCallback;
+
+  CefSoftwareOutputDeviceOSR(ui::Compositor* compositor,
+                             bool transparent,
+                             const OnPaintCallback& callback);
+  ~CefSoftwareOutputDeviceOSR() override;
+
+  // cc::SoftwareOutputDevice implementation.
+  void Resize(const gfx::Size& viewport_pixel_size,
+             float scale_factor) override;
+  SkCanvas* BeginPaint(const gfx::Rect& damage_rect) override;
+  void EndPaint(cc::SoftwareFrameData* frame_data) override;
+  void CopyToPixels(const gfx::Rect& rect, void* pixels) override;
+
+  void SetActive(bool active);
+
+  // Include |damage_rect| the next time OnPaint is called.
+  void Invalidate(const gfx::Rect& damage_rect);
+
+  // Deliver the OnPaint notification immediately.
+  void OnPaint(const gfx::Rect& damage_rect);
+
+ private:
+  const bool transparent_;
+  const OnPaintCallback callback_;
+
+  bool active_;
+  scoped_ptr<SkCanvas> canvas_;
+  scoped_ptr<SkBitmap> bitmap_;
+  gfx::Rect pending_damage_rect_;
+
+  DISALLOW_COPY_AND_ASSIGN(CefSoftwareOutputDeviceOSR);
+};
+
+#endif  // CEF_LIBCEF_BROWSER_SOFTWARE_OUTPUT_DEVICE_OSR_H_