Generalize browser controls adjustment for arbitrary scrollers.

third_party/WebKit/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 1828 matching lines @@
     // document and restore it when the object goes out of scope. It's
     // needed since the browser controls adjustment will change the maximum
     // scroll offset and we may need to reposition them to keep the user's
     // apparent position unchanged.
     ResizeViewportAnchor::ResizeScope resizeScope(*m_resizeViewportAnchor);
 
     float browserControlsViewportAdjustment =
         browserControls().layoutHeight() - browserControls().contentOffset();
     visualViewport.setBrowserControlsAdjustment(
         browserControlsViewportAdjustment);
-
-    // Since the FrameView is sized to be the visual viewport at minimum
-    // scale, its adjustment must also be scaled by the minimum scale.
-    view->setBrowserControlsViewportAdjustment(
-        browserControlsViewportAdjustment / minimumPageScaleFactor());
   }
 }
 
 BrowserControls& WebViewImpl::browserControls() {
   return page()->frameHost().browserControls();
 }
 
 void WebViewImpl::resizeViewWhileAnchored(float browserControlsHeight,
                                           bool browserControlsShrinkLayout) {
   DCHECK(mainFrameImpl());
@@ skipping 2331 matching lines @@
   if (focusedFrame->localFrameRoot() != mainFrameImpl()->frame())
     return nullptr;
   return focusedFrame;
 }
 
 LocalFrame* WebViewImpl::focusedLocalFrameAvailableForIme() const {
   return m_imeAcceptEvents ? focusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink