Fix crash when computing media controls width for out of process iframe

third_party/WebKit/Source/core/layout/LayoutMedia.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 141 matching lines @@
 }
 
 void LayoutMedia::setRequestPositionUpdates(bool want) {
   if (want)
     view()->registerMediaForPositionChangeNotification(*this);
   else
     view()->unregisterMediaForPositionChangeNotification(*this);
 }
 
 LayoutUnit LayoutMedia::computePanelWidth(const LayoutRect& mediaRect) const {
+  // We don't know if the main frame has an horizontal scrollbar if it is out of
+  // process.
+  if (document().page()->mainFrame()->isRemoteFrame())

[dcheng, 2016/11/04 16:48:36]

What breaks if we don't go through the rest of this path for OOPIF? Do we need
to handle that case at some point?

[mlamouri (slow - plz ping), 2016/11/04 17:00:56]

The feature is meant to make the default controls resize to match the viewport
if the user can't scroll horizontally. It's mostly targeted for mobile (but
would work on desktop though). On OOPIF, it would behave exactly like today
where part of the controls are not visible. It's not ideal but not a serious
concerns especially given that OOPIF might not be enabled on Android any time
soon, right?

[mlamouri (slow - plz ping), 2016/11/04 18:17:55]

Do you want me to file a bug and add a TODO?

+    return mediaRect.width();
+
   FrameHost* frameHost = document().frameHost();
   LocalFrame* mainFrame = document().page()->deprecatedLocalMainFrame();
   FrameView* pageView = mainFrame ? mainFrame->view() : nullptr;
   if (!frameHost || !mainFrame || !pageView)
     return mediaRect.width();
 
   if (pageView->horizontalScrollbarMode() != ScrollbarAlwaysOff)
     return mediaRect.width();
 
   // On desktop, this will include scrollbars when they stay visible.
   const LayoutUnit visibleWidth(frameHost->visualViewport().visibleWidth());
   const LayoutUnit absoluteXOffset(
       localToAbsolute(
           FloatPoint(mediaRect.location()),
           UseTransforms | ApplyContainerFlip | TraverseDocumentBoundaries)
           .x());
   DCHECK_GE(visibleWidth - absoluteXOffset, 0);
 
   return std::min(mediaRect.width(), visibleWidth - absoluteXOffset);
 }
 
 }  // namespace blink