Simplify ScreenCapturer interface.

media/video/capture/screen/screen_capturer_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/video/capture/screen/screen_capturer.h"
 
 #include <windows.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 62 matching lines @@
 // ScreenCapturerWin captures 32bit RGB using GDI.
 //
 // ScreenCapturerWin is double-buffered as required by ScreenCapturer.
 class ScreenCapturerWin : public ScreenCapturer {
  public:
   ScreenCapturerWin();
   virtual ~ScreenCapturerWin();
 
   // Overridden from ScreenCapturer:
   virtual void Start(Delegate* delegate) OVERRIDE;
-  virtual void Stop() OVERRIDE;
-  virtual void InvalidateRegion(const SkRegion& invalid_region) OVERRIDE;
   virtual void CaptureFrame() OVERRIDE;
 
  private:
   // Make sure that the device contexts match the screen configuration.
   void PrepareCaptureResources();
 
   // Creates a ScreenCaptureData instance wrapping the current framebuffer and
   // notifies |delegate_|.
   void CaptureRegion(const SkRegion& region,
                      const base::Time& capture_start_time);
@@ skipping 109 matching lines @@
 }
 
 ScreenCapturerWin::ScreenCapturerWin()
     : delegate_(NULL),
       desktop_dc_rect_(SkIRect::MakeEmpty()),
       composition_func_(NULL),
       set_thread_execution_state_failed_(false) {
 }
 
 ScreenCapturerWin::~ScreenCapturerWin() {
-}
+  // Restore Aero.
+  if (composition_func_ != NULL) {
+    (*composition_func_)(DWM_EC_ENABLECOMPOSITION);
+  }
 
-void ScreenCapturerWin::InvalidateRegion(const SkRegion& invalid_region) {
-  helper_.InvalidateRegion(invalid_region);
+  delegate_ = NULL;
 }
 
 void ScreenCapturerWin::CaptureFrame() {
   base::Time capture_start_time = base::Time::Now();
 
   // Request that the system not power-down the system, or the display hardware.
   if (!SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)) {
     if (!set_thread_execution_state_failed_) {
       set_thread_execution_state_failed_ = true;
       LOG_GETLASTERROR(WARNING)
@@ skipping 19 matching lines @@
       differ_.reset(new Differ(current_buffer->dimensions().width(),
                                current_buffer->dimensions().height(),
                                ScreenCaptureData::kBytesPerPixel,
                                current_buffer->bytes_per_row()));
     }
 
     // Calculate difference between the two last captured frames.
     SkRegion region;
     differ_->CalcDirtyRegion(last_buffer->pixels(), current_buffer->pixels(),
                              &region);
-    InvalidateRegion(region);
+    helper_.InvalidateRegion(region);
   } else {
     // No previous frame is available. Invalidate the whole screen.
     helper_.InvalidateScreen(current_buffer->dimensions());
   }
 
   // Wrap the captured frame into ScreenCaptureData structure and invoke
   // the completion callback.
   SkRegion invalid_region;
   helper_.SwapInvalidRegion(&invalid_region);
   CaptureRegion(invalid_region, capture_start_time);
@@ skipping 20 matching lines @@
   }
 
   // Vote to disable Aero composited desktop effects while capturing. Windows
   // will restore Aero automatically if the process exits. This has no effect
   // under Windows 8 or higher.  See crbug.com/124018.
   if (composition_func_ != NULL) {
     (*composition_func_)(DWM_EC_DISABLECOMPOSITION);
   }
 }
 
-void ScreenCapturerWin::Stop() {
-  // Restore Aero.
-  if (composition_func_ != NULL) {
-    (*composition_func_)(DWM_EC_ENABLECOMPOSITION);
-  }
-
-  delegate_ = NULL;
-}
-
 void ScreenCapturerWin::PrepareCaptureResources() {
   // Switch to the desktop receiving user input if different from the current
   // one.
   scoped_ptr<Desktop> input_desktop = Desktop::GetInputDesktop();
   if (input_desktop.get() != NULL && !desktop_.IsSame(*input_desktop)) {
     // Release GDI resources otherwise SetThreadDesktop will fail.
     desktop_dc_.reset();
     memory_dc_.Set(NULL);
 
     // If SetThreadDesktop() fails, the thread is still assigned a desktop.
@@ skipping 282 matching lines @@
 void ScreenCapturer::Delegate::ReleaseSharedBuffer(
     scoped_refptr<SharedBuffer> buffer) {
 }
 
 // static
 scoped_ptr<ScreenCapturer> ScreenCapturer::Create() {
   return scoped_ptr<ScreenCapturer>(new ScreenCapturerWin());
 }
 
 }  // namespace media