[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/desktop_frame_generator.h

Index: webrtc/modules/desktop_capture/desktop_frame_generator.h
diff --git a/webrtc/modules/desktop_capture/desktop_frame_generator.h b/webrtc/modules/desktop_capture/desktop_frame_generator.h
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index 0000000000000000000000000000000000000000..2b767dcb4dd3c5ff511f27f70c0a9a39bb3e0d20
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+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_GENERATOR_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_GENERATOR_H_
+
+#include <memory>
+
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+#include "webrtc/modules/desktop_capture/shared_memory.h"
+
+namespace webrtc {
+
+// An interface to generate a DesktopFrame.
+class DesktopFrameGenerator {
+ public:
+  DesktopFrameGenerator();
+  virtual ~DesktopFrameGenerator();
+
+  virtual std::unique_ptr<DesktopFrame> GetNextFrame(
+      SharedMemoryFactory* factory) = 0;
+};
+
+// An interface to paint a DesktopFrame. This interface is used by
+// PainterDesktopFrameGenerator.
+class DesktopFramePainter {
+ public:
+  DesktopFramePainter();
+  virtual ~DesktopFramePainter();
+
+  virtual bool Paint(DesktopFrame* frame, DesktopRegion* updated_region) = 0;
+};
+
+// An implementation of DesktopFrameGenerator to take care about the
+// DesktopFrame size, filling updated_region(), etc, but leaves the real
+// painting work to a DesktopFramePainter implementation.
+class PainterDesktopFrameGenerator final : public DesktopFrameGenerator {
+ public:
+  PainterDesktopFrameGenerator();
+  ~PainterDesktopFrameGenerator() override;
+
+  std::unique_ptr<DesktopFrame> GetNextFrame(
+      SharedMemoryFactory* factory) override;
+
+  // Sets the size of the frame which will be returned in next GetNextFrame()
+  // call.
+  DesktopSize* size();
+
+  // Decides whether BaseDesktopFrameGenerator returns a frame in next Capture()
+  // callback. If return_frame_ is true, BaseDesktopFrameGenerator will create a
+  // frame according to both size_ and SharedMemoryFactory input, and uses
+  // Paint() function to paint it.
+  void set_return_frame(bool return_frame);
+
+  // Decides whether MockScreenCapturer returns a frame with updated regions.
+  // MockScreenCapturer will keep DesktopFrame::updated_region() empty if this
+  // field is false.
+  void set_provide_updated_region_hints(bool provide_updated_region_hints);
+
+  // Decides whether MockScreenCapturer randomly enlarges updated regions in the
+  // DesktopFrame. Set this field to true to simulate an inaccurate updated
+  // regions' return from OS APIs.
+  void set_enlarge_updated_region(bool enlarge_updated_region);
+
+  // The range to enlarge a updated region if |enlarge_updated_region_| is true.
+  // If this field is less than zero, it will be treated as zero, and
+  // |enlarge_updated_region_| will be ignored.
+  void set_enlarge_range(int enlarge_range);
+
+  // Decides whether BaseDesktopFrameGenerator randomly add some updated regions
+  // in the DesktopFrame. Set this field to true to simulate an inaccurate
+  // updated regions' return from OS APIs.
+  void set_add_random_updated_region(bool add_random_updated_region);
+
+  // Sets the painter object to do the real painting work, if no |painter_| has
+  // been set to this instance, the DesktopFrame returned by GetNextFrame()
+  // function will keep in an undefined but valid state.
+  // PainterDesktopFrameGenerator does not take ownership of the |painter|.
+  void set_desktop_frame_painter(DesktopFramePainter* painter);
+
+ private:
+  DesktopSize size_;
+  bool return_frame_;
+  bool provide_updated_region_hints_;
+  bool enlarge_updated_region_;
+  int enlarge_range_;
+  bool add_random_updated_region_;
+  DesktopFramePainter* painter_;
+};
+
+// An implementation of DesktopFramePainter to paint black on
+// mutable_updated_region(), and white elsewhere.
+class BlackWhiteDesktopFramePainter final : public DesktopFramePainter {
+ public:
+  BlackWhiteDesktopFramePainter();
+  ~BlackWhiteDesktopFramePainter() override;
+
+  // The black regions of the frame which will be returned in next Paint()
+  // call. BlackWhiteDesktopFramePainter will draw a white frame, with black
+  // in the updated_region_. Each Paint() call will consume updated_region_.
+  DesktopRegion* updated_region();
+
+  // DesktopFramePainter interface.
+  bool Paint(DesktopFrame* frame, DesktopRegion* updated_region) override;
+
+ private:
+  DesktopRegion updated_region_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_GENERATOR_H_