Fix page zoom to be frame-centric for out-of-process frames.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 377 matching lines @@
 {
     IntRect oldRect = frameRect();
     if (newRect == oldRect)
         return;
 
     Widget::setFrameRect(newRect);
 
     const bool frameSizeChanged = oldRect.size() != newRect.size();
 
     m_needsScrollbarsUpdate = frameSizeChanged;
-    // If layout is clean then update scrollbars immediately otherwise wait
-    // for layout to ensure content size is correct too.
-    if (!needsLayout())
-        updateScrollbarsIfNeeded();
+    // TODO(wjmaclean): find out why scrollbars fail to resize for complex
+    // subframes after changing the zoom level. For now always calling
+    // updateScrollbarsIfNeeded() here fixes the issue, but it would be good to
+    // discover the deeper cause of this.
+    // http://crbug.com/000000 <-- Don't land without filing this bug
+    updateScrollbarsIfNeeded();
 
     frameRectsChanged();
 
     updateScrollableAreaSet();
 
     if (LayoutViewItem layoutView = this->layoutViewItem()) {
         // TODO(majidvp): It seems that this only needs to be called when size
         // is updated ignoring any change in the location.
         if (layoutView.usesCompositing())
             layoutView.compositor()->frameViewDidChangeSize();
@@ skipping 3687 matching lines @@
     return m_hiddenForThrottling && m_crossOriginForThrottling;
 }
 
 LayoutBox& FrameView::boxForScrollControlPaintInvalidation() const
 {
     ASSERT(layoutView());
     return *layoutView();
 }
 
 } // namespace blink