Fix ScreenCapturerWinGdi to handle DesktopFrameWin::Create() errors.

webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
index 352433e1cdb5d79526e4ad5b6be518c31c5e1219..4d76fce0fa28d58a33b1d164c8594864dfd74117 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
@@ -241,9 +241,10 @@ bool ScreenCapturerWinGdi::CaptureImage() {
         DesktopFrame::kBytesPerPixel;
     SharedMemory* shared_memory = callback_->CreateSharedMemory(buffer_size);
 
-    rtc::scoped_ptr<DesktopFrame> buffer;
-    buffer.reset(
+    rtc::scoped_ptr<DesktopFrame> buffer(
         DesktopFrameWin::Create(size, shared_memory, desktop_dc_));
+    if (!buffer.get())
+      return false;
     queue_.ReplaceCurrentFrame(buffer.release());
   }