[DesktopCapture] Detect screen resolution changes in DirectX capturer

webrtc/modules/desktop_capture/win/dxgi_texture.h

Index: webrtc/modules/desktop_capture/win/dxgi_texture.h
diff --git a/webrtc/modules/desktop_capture/win/dxgi_texture.h b/webrtc/modules/desktop_capture/win/dxgi_texture.h
index a4bd237e01e33fea4615b1538654399c56449748..06b49547f0b6d95458ad75d2efb0924046757851 100644
--- a/webrtc/modules/desktop_capture/win/dxgi_texture.h
+++ b/webrtc/modules/desktop_capture/win/dxgi_texture.h
@@ -11,12 +11,14 @@
 #ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_TEXTURE_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_TEXTURE_H_
 
+#include <D3D11.h>
 #include <DXGI1_2.h>
 
 #include <memory>
 
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/resolution_change_detector.h"
 
 namespace webrtc {
 
@@ -27,14 +29,14 @@ class DxgiTexture {
  public:
   // Creates a DxgiTexture instance, which represents the |desktop_size| area of
   // entire screen -- usually a monitor on the system.
-  explicit DxgiTexture(const DesktopSize& desktop_size);
+  DxgiTexture();
 
   virtual ~DxgiTexture();
 
   // Copies selected regions of a frame represented by frame_info and resource.
   // Returns false if anything wrong.
-  virtual bool CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
-                        IDXGIResource* resource) = 0;
+  bool CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                IDXGIResource* resource);
 
   const DesktopSize& desktop_size() const { return desktop_size_; }
 
@@ -57,10 +59,14 @@ class DxgiTexture {
   DXGI_MAPPED_RECT rect_ = {0};

[Sergey Ulanov, 2017/02/15 01:38:52]

BTW, style guide doesn't allow protected data fields, only methods.

 
  private:
+  virtual bool CopyFromTexture(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                               ID3D11Texture2D* texture) = 0;
+
   virtual bool DoRelease() = 0;

[Sergey Ulanov, 2017/02/10 19:58:25]

These two methods are intended to be overwritten by children. It's better to
make the protected to make this clear.

[Hzj_jie, 2017/02/11 01:51:22]

In C++, private functions are also overrideable, though not accessible. Do we
always prefer to use protected here? These two functions should not be called
directly by derived classes, though technically derived classes can still access
these functionalities.

[Sergey Ulanov, 2017/02/15 01:38:51]

Right, private methods can still be overridden, but putting them in the
protected makes it clear that child classes need to override these methods .
Children can still call these methods directly because they will override them,
so you don't gain anything by declaring them in the private section here.

[Hzj_jie, 2017/02/15 03:53:16]

I have no opinion on this. Indeed, some modern languages do no t support private
overridable functions, which resolves this issue permanently.
I have updated the code here.

 
-  const DesktopSize desktop_size_;
+  DesktopSize desktop_size_;
   std::unique_ptr<DesktopFrame> frame_;
+  ResolutionChangeDetector resolution_change_detector_;
 };
 
 }  // namespace webrtc