OOPIF: Check whether localFrameRootTemporary is valid when processing resizing messages

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1694 matching lines @@
 }
 
 void WebViewImpl::setTopControlsLayoutHeight(float height)
 {
     m_topControlsLayoutHeight = height;
     didUpdateTopControls();
 }
 
 void WebViewImpl::didUpdateTopControls()
 {
-    FrameView* view = localFrameRootTemporary()->frameView();
+    WebLocalFrameImpl* localFrameRoot = localFrameRootTemporary();
+    if (!localFrameRoot)
+        return;
+
+    FrameView* view = localFrameRoot->frameView();
     if (!view)
         return;
 
     // The viewport bounds were adjusted on the compositor by this much due to top controls. Tell
     // the FrameView about it so it can make correct scroll offset clamping decisions during compositor
     // commits.
     // FIXME(bokan) Reenable once Chromium side lands.
     // float topControlsViewportAdjustment = m_topControlsContentOffset - m_topControlsLayoutHeight;
     // view->setTopControlsViewportAdjustment(topControlsViewportAdjustment);
 }
 
 void WebViewImpl::resize(const WebSize& newSize)
 {
     if (m_shouldAutoResize || m_size == newSize)
         return;
 
-    FrameView* view = localFrameRootTemporary()->frameView();
+    // FIXME: if a remote frame is swapped back in, it may have the wrong
+    // sizing.

[kenrb, 2014/10/10 19:20:21]

I don't think this is a valid concern. Size messages should be destined to the
process where a frame is actually being rendered. A remote frame's embedder
knows how big the frame is supposed to be, and it is sending that size to the
process where the frame is local.

Ultimately WebViewImpl::resize() should only be called on the top-level frame,
because semantically this is declaring the size of the content viewport in the
browser window. Part of getting rid of localFrameRootTemporary() is making
WebViewImpl not have to route messages to remote frames.

+    WebLocalFrameImpl* localFrameRoot = localFrameRootTemporary();
+    if (!localFrameRoot)
+        return;
+
+    FrameView* view = localFrameRoot->frameView();
     if (!view)
         return;
 
     bool shouldAnchorAndRescaleViewport = settings()->mainFrameResizesAreOrientationChanges()
         && m_size.width && contentsSize().width() && newSize.width != m_size.width && !m_fullscreenController->isFullscreen();
     float oldPageScaleFactor = pageScaleFactor();
     float oldMinimumPageScaleFactor = minimumPageScaleFactor();
 
     m_size = newSize;
 
@@ skipping 2695 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink