Media Controls: don't "cut" controls if fully hidden.

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 162 matching lines @@
   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);
+  const LayoutUnit newWidth = visibleWidth - absoluteXOffset;
+
+  if (newWidth < 0)
+    return mediaRect.width();
 
   return std::min(mediaRect.width(), visibleWidth - absoluteXOffset);
 }
 
 }  // namespace blink