Make PageScaleFactor work for oopif subframes.

third_party/WebKit/Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
@@ skipping 1424 matching lines @@
     // is an old version of HistoryItem so distribute the scroll between
     // the main frame and the visual viewport as best as we can.
     if (visualViewportOffset.width() == -1 &&
         visualViewportOffset.height() == -1) {
       visualViewportOffset =
           m_currentItem->getScrollOffset() -
           view->layoutViewportScrollableArea()->getScrollOffset();
     }
 
     VisualViewport& visualViewport = m_frame->host()->visualViewport();
+    float originalScale = visualViewport.scale();
     if (shouldRestoreScale && shouldRestoreScroll) {
       visualViewport.setScaleAndLocation(m_currentItem->pageScaleFactor(),
                                          FloatPoint(visualViewportOffset));
     } else if (shouldRestoreScale) {
       visualViewport.setScale(m_currentItem->pageScaleFactor());
     } else if (shouldRestoreScroll) {
       visualViewport.setLocation(FloatPoint(visualViewportOffset));
     }
+    // If necessary, notify client we've restored page scale.
+    if (shouldRestoreScale && (originalScale != visualViewport.scale()))
+      client()->didRestorePageScaleFactorOnLoad(visualViewport.scale());
 
     if (ScrollingCoordinator* scrollingCoordinator =
             m_frame->page()->scrollingCoordinator())
       scrollingCoordinator->frameViewRootLayerDidChange(view);
   }
 
   documentLoader()->initialScrollState().didRestoreFromHistory = true;
 }
 
 String FrameLoader::userAgent() const {
@@ skipping 464 matching lines @@
                          m_documentLoader ? m_documentLoader->url() : String());
   return tracedValue;
 }
 
 inline void FrameLoader::takeObjectSnapshot() const {
   TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID("loading", "FrameLoader", this,
                                       toTracedValue());
 }
 
 }  // namespace blink