Update visual viewport API to take browser zoom into account.

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

 /*
  * Copyright (C) 2013 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 193 matching lines @@
     setLocation(m_offset + delta);
 }
 
 void VisualViewport::setScale(float scale)
 {
     setScaleAndLocation(scale, m_offset);
 }
 
 double VisualViewport::scrollLeft()
 {
+    if (!mainFrame())
+        return 0;
+
     updateLayoutIgnorePendingStylesheets();
 
-    return visibleRect().x();
+    return adjustScrollForAbsoluteZoom(visibleRect().x(), mainFrame()->pageZoomFactor());
 }
 
 double VisualViewport::scrollTop()
 {
+    if (!mainFrame())
+        return 0;
+
     updateLayoutIgnorePendingStylesheets();
 
-    return visibleRect().y();
+    return adjustScrollForAbsoluteZoom(visibleRect().y(), mainFrame()->pageZoomFactor());
 }
 
 void VisualViewport::setScrollLeft(double x)
 {
+    if (!mainFrame())
+        return;
+
     updateLayoutIgnorePendingStylesheets();
 
-    setLocation(FloatPoint(x, visibleRect().y()));
+    setLocation(FloatPoint(x * mainFrame()->pageZoomFactor(), location().y()));
 }
 
 void VisualViewport::setScrollTop(double y)
 {
+    if (!mainFrame())
+        return;
+
     updateLayoutIgnorePendingStylesheets();
 
-    setLocation(FloatPoint(visibleRect().x(), y));
+    setLocation(FloatPoint(location().x(), y * mainFrame()->pageZoomFactor()));
 }
 
 double VisualViewport::clientWidth()
 {
+    if (!mainFrame())
+        return 0;
+
     updateLayoutIgnorePendingStylesheets();
 
-    return visibleRect().width();
+    return adjustScrollForAbsoluteZoom(visibleSize().width(), mainFrame()->pageZoomFactor());
 }
 
 double VisualViewport::clientHeight()
 {
+    if (!mainFrame())
+        return 0;
+
     updateLayoutIgnorePendingStylesheets();
 
-    return visibleRect().height();
+    return adjustScrollForAbsoluteZoom(visibleSize().height(), mainFrame()->pageZoomFactor());
 }
 
 double VisualViewport::pageScale()
 {
     updateLayoutIgnorePendingStylesheets();
 
     return m_scale;
 }
 
 void VisualViewport::setScaleAndLocation(float scale, const FloatPoint& location)
@@ skipping 552 matching lines @@
     } else if (graphicsLayer == m_rootTransformLayer) {
         name =  "Root Transform Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink