Make PageScaleFactor work for oopif subframes.

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

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index 24b4a63d43c5123611eee2045d8400145599a277..d00788375e1777320690be32430200d15521c850 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -1442,6 +1442,7 @@ void FrameLoader::restoreScrollPositionAndViewState() {
     }
 
     VisualViewport& visualViewport = m_frame->host()->visualViewport();
+    float originalScale = visualViewport.scale();
     if (shouldRestoreScale && shouldRestoreScroll) {
       visualViewport.setScaleAndLocation(m_currentItem->pageScaleFactor(),
                                          FloatPoint(visualViewportOffset));
@@ -1450,6 +1451,9 @@ void FrameLoader::restoreScrollPositionAndViewState() {
     } 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())