[WebRTC] Implement Windows ScreenDrawer to test ScreenCapturer*

webrtc/modules/desktop_capture/screen_drawer_linux.h

+/*
+ *  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 MODULES_DESKTOP_CAPTURE_SCREEN_DRAWER_LINUX_H_

[Sergey Ulanov, 2016/08/09 17:43:01]

For platform-specific screen capturers we don't have .h files. Instead the
corresponding classes are declared in .cc file. Follow the same pattern here? 

[Sergey Ulanov, 2016/08/09 17:43:01]

This file should be called screen_drawer_x11.h

[Hzj_jie, 2016/08/11 18:42:04]

I thought linux suffix can trigger GN / GYP exclusive rule for other platforms.
But I am happy to rename this class to ScreenDrawerLinux.

[Hzj_jie, 2016/08/11 18:42:04]

Done.

+#define MODULES_DESKTOP_CAPTURE_SCREEN_DRAWER_LINUX_H_
+
+#include "webrtc/modules/desktop_capture/screen_drawer.h"
+#include "webrtc/modules/desktop_capture/x11/shared_x_display.h"
+
+namespace webrtc {
+
+// A ScreenDrawer implementation for X11dows.

[Sergey Ulanov, 2016/08/09 17:43:01]

typo: X11dows

[Hzj_jie, 2016/08/11 18:42:04]

Done.

+class ScreenDrawerX11 : public ScreenDrawer {
+ public:
+  ScreenDrawerX11();
+  ~ScreenDrawerX11() override;
+
+  DesktopRect DrawableRegion() override;

[Sergey Ulanov, 2016/08/09 17:43:01]

// ScreenDrawer interface.

[Hzj_jie, 2016/08/11 18:42:04]

Done.

+  void DrawRectangle(DesktopRect rect, uint32_t rgba) override;
+
+ private:
+  const rtc::scoped_refptr<SharedXDisplay> display_;
+  const Screen* screen_;
+  const int screen_num_;
+  const DesktopRect rect_;
+  Window window_;
+  GC context_;
+  Colormap colormap_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_DESKTOP_CAPTURE_SCREEN_DRAWER_LINUX_H_