Revert of Remove ignored return code from modules.

webrtc/modules/video_render/video_render_impl.cc

 /*
  *  Copyright (c) 2012 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 101 matching lines @@
                 break;
         }
     }
 }
 
 int64_t ModuleVideoRenderImpl::TimeUntilNextProcess()
 {
     // Not used
     return 50;
 }
-void ModuleVideoRenderImpl::Process() {}
+int32_t ModuleVideoRenderImpl::Process()
+{
+    // Not used
+    return 0;
+}
 
 void*
 ModuleVideoRenderImpl::Window()
 {
     CriticalSectionScoped cs(&_moduleCrit);
     return _ptrWindow;
 }
 
 int32_t ModuleVideoRenderImpl::ChangeWindow(void* window)
 {
@@ skipping 458 matching lines @@
         // This stream doesn't exist
         WEBRTC_TRACE(kTraceError, kTraceVideoRenderer, _id,
                      "%s: stream doesn't exist", __FUNCTION__);
         return -1;
     }
     assert(item->second != NULL);
     return item->second->SetTimeoutImage(videoFrame, timeout);
 }
 
 }  // namespace webrtc