DirectX based screen capturer logic

webrtc/modules/desktop_capture/screen_capture_frame_queue.h

Index: webrtc/modules/desktop_capture/screen_capture_frame_queue.h
diff --git a/webrtc/modules/desktop_capture/screen_capture_frame_queue.h b/webrtc/modules/desktop_capture/screen_capture_frame_queue.h
index 21af0f320fc277952c4515b547d9ab98492a2a15..b15ae4bc733e8f05d2d6b0660a43fb244c0ad3f7 100644
--- a/webrtc/modules/desktop_capture/screen_capture_frame_queue.h
+++ b/webrtc/modules/desktop_capture/screen_capture_frame_queue.h
@@ -13,8 +13,8 @@
 
 #include <memory>
 
+#include "webrtc/modules/desktop_capture/screen_capture_content_queue.h"
 #include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
-#include "webrtc/typedefs.h"
 
 namespace webrtc {
 class DesktopFrame;
@@ -35,10 +35,16 @@ namespace webrtc {
 // Frame consumer is expected to never hold more than kQueueLength frames
 // created by this function and it should release the earliest one before trying
 // to capture a new frame (i.e. before MoveToNextFrame() is called).
-class ScreenCaptureFrameQueue {
+//
+// Users do not expect to call functions from
+// ScreenCaptureContentQueue<SharedDesktopFrame>, since extra assertions or
+// wrappers are applied.
+class ScreenCaptureFrameQueue : ScreenCaptureContentQueue<SharedDesktopFrame> {
  public:
-  ScreenCaptureFrameQueue();
-  ~ScreenCaptureFrameQueue();
+  ScreenCaptureFrameQueue() = default;
+  virtual ~ScreenCaptureFrameQueue() = default;
+
+  using ScreenCaptureContentQueue<SharedDesktopFrame>::Reset;
 
   // Moves to the next frame in the queue, moving the 'current' frame to become
   // the 'previous' one.
@@ -48,25 +54,14 @@ class ScreenCaptureFrameQueue {
   // existing frame (if any) is destroyed. Takes ownership of |frame|.
   void ReplaceCurrentFrame(DesktopFrame* frame);
 
-  // Marks all frames obsolete and resets the previous frame pointer. No
-  // frames are freed though as the caller can still access them.
-  void Reset();
-
   SharedDesktopFrame* current_frame() const {
-    return frames_[current_].get();
+    return current();
   }
 
   SharedDesktopFrame* previous_frame() const {
-    return frames_[(current_ + kQueueLength - 1) % kQueueLength].get();
+    return previous();
   }
 
- private:
-  // Index of the current frame.
-  int current_;
-
-  static const int kQueueLength = 2;
-  std::unique_ptr<SharedDesktopFrame> frames_[kQueueLength];
-
   RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCaptureFrameQueue);
 };