Update XServerPixelBuffer to handle errors returned from XGetImage().

webrtc/modules/desktop_capture/screen_capturer_x11.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 238 matching lines @@
   // If the current frame is from an older generation then allocate a new one.
   // Note that we can't reallocate other buffers at this point, since the caller
   // may still be reading from them.
   if (!queue_.current_frame()) {
     queue_.ReplaceCurrentFrame(
         SharedDesktopFrame::Wrap(std::unique_ptr<DesktopFrame>(
             new BasicDesktopFrame(x_server_pixel_buffer_.window_size()))));
   }
 
   std::unique_ptr<DesktopFrame> result = CaptureScreen();
+  if (!result) {
+    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
+    return;
+  }
+
   last_invalid_region_ = result->updated_region();
   result->set_capture_time_ms((rtc::TimeNanos() - capture_start_time_nanos) /
                               rtc::kNumNanosecsPerMillisec);
   callback_->OnCaptureResult(Result::SUCCESS, std::move(result));
 }
 
 bool ScreenCapturerLinux::GetScreenList(ScreenList* screens) {
   RTC_DCHECK(screens->size() == 0);
   // TODO(jiayl): implement screen enumeration.
   Screen default_screen;
@@ skipping 58 matching lines @@
     helper_.TakeInvalidRegion(updated_region);
 
     // Clip the damaged portions to the current screen size, just in case some
     // spurious XDamage notifications were received for a previous (larger)
     // screen size.
     updated_region->IntersectWith(
         DesktopRect::MakeSize(x_server_pixel_buffer_.window_size()));
 
     for (DesktopRegion::Iterator it(*updated_region);
          !it.IsAtEnd(); it.Advance()) {
-      x_server_pixel_buffer_.CaptureRect(it.rect(), frame.get());
+      if (!x_server_pixel_buffer_.CaptureRect(it.rect(), frame.get()))
+        return nullptr;
     }
   } else {
     // Doing full-screen polling, or this is the first capture after a
     // screen-resolution change.  In either case, need a full-screen capture.
     DesktopRect screen_rect = DesktopRect::MakeSize(frame->size());
     x_server_pixel_buffer_.CaptureRect(screen_rect, frame.get());
     updated_region->SetRect(screen_rect);
   }
 
   return std::move(frame);
@@ skipping 64 matching lines @@
   }
 
   if (options.detect_updated_region()) {
     capturer.reset(new ScreenCapturerDifferWrapper(std::move(capturer)));
   }
 
   return capturer.release();
 }
 
 }  // namespace webrtc