Revert of Use std::unique_ptr<> to pass frame ownership in DesktopCapturer impls.

webrtc/modules/desktop_capture/desktop_capturer.h

Index: webrtc/modules/desktop_capture/desktop_capturer.h
diff --git a/webrtc/modules/desktop_capture/desktop_capturer.h b/webrtc/modules/desktop_capture/desktop_capturer.h
index 80d910908b4fe213bb1f139795b329f2446de61f..ba70e0155373410475cff8b27a8362bae453b265 100644
--- a/webrtc/modules/desktop_capture/desktop_capturer.h
+++ b/webrtc/modules/desktop_capture/desktop_capturer.h
@@ -15,45 +15,24 @@
 
 #include <memory>
 
-#include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_capture_types.h"
 #include "webrtc/modules/desktop_capture/shared_memory.h"
 
 namespace webrtc {
 
 class DesktopFrame;
+class DesktopRegion;
 
 // Abstract interface for screen and window capturers.
 class DesktopCapturer {
  public:
-  enum class Result {
-    // The frame was captured successfully.
-    SUCCESS,
-
-    // There was a temporary error. The caller should continue calling
-    // Capture(), in the expectation that it will eventually recover.
-    ERROR_TEMPORARY,
-
-    // Capture has failed and will keep failing if the caller tries calling
-    // Capture() again.
-    ERROR_PERMANENT,
-  };
-
   // Interface that must be implemented by the DesktopCapturer consumers.
   class Callback {
    public:
-    // Called after a frame has been captured. |frame| is not nullptr if and
-    // only if |result| is SUCCESS.
-    virtual void OnCaptureResult(Result result,
-                                 std::unique_ptr<DesktopFrame> frame) {
-      OnCaptureCompleted(frame.release());
-    }
-
-    // Deprecated version of the method above that uses raw pointer instead of
-    // std::unique_ptr<>.
-    // TODO(sergeyu): Remove this method and make OnCaptureResult() pure
-    // virtual. crbug.com/webrtc/5950
-    virtual void OnCaptureCompleted(DesktopFrame* frame) { delete frame; };
+    // Called after a frame has been captured. Handler must take ownership of
+    // |frame|. If capture has failed for any reason |frame| is set to NULL
+    // (e.g. the window has been closed).
+    virtual void OnCaptureCompleted(DesktopFrame* frame) = 0;
 
    protected:
     virtual ~Callback() {}