Normalize top controls offset to (0, 1), Blink-side.

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 395 matching lines @@
     , m_showFPSCounter(false)
     , m_showPaintRects(false)
     , m_showDebugBorders(false)
     , m_continuousPaintingEnabled(false)
     , m_showScrollBottleneckRects(false)
     , m_baseBackgroundColor(Color::white)
     , m_backgroundColorOverride(Color::transparent)
     , m_zoomFactorOverride(0)
     , m_userGestureObserved(false)
     , m_topControlsContentOffset(0)
-    , m_topControlsLayoutHeight(0)
+    , m_topControlsHeight(0)
+    , m_topControlsShrinkLayoutSize(true)
+    , m_topControlsOffsetIsNormalized(true)
 {
     Page::PageClients pageClients;
     pageClients.chromeClient = &m_chromeClientImpl;
     pageClients.contextMenuClient = &m_contextMenuClientImpl;
     pageClients.editorClient = &m_editorClientImpl;
     pageClients.dragClient = &m_dragClientImpl;
     pageClients.inspectorClient = &m_inspectorClientImpl;
     pageClients.spellCheckerClient = &m_spellCheckerClientImpl;
 
     m_page = adoptPtrWillBeNoop(new Page(pageClients));
@@ skipping 1292 matching lines @@
 
 void WebViewImpl::setTopControlsContentOffset(float offset)
 {
     m_topControlsContentOffset = offset;
     m_layerTreeView->setTopControlsContentOffset(offset);
     didUpdateTopControls();
 }
 
 void WebViewImpl::setTopControlsLayoutHeight(float height)
 {
-    m_topControlsLayoutHeight = height;
+    m_topControlsOffsetIsNormalized = false;
+    setTopControlsHeight(height, true);
+}
+
+void WebViewImpl::setTopControlsHeight(float height, bool topControlsShrinkLayoutSize)
+{
+    if (m_topControlsHeight == height && m_topControlsShrinkLayoutSize == topControlsShrinkLayoutSize)
+        return;
+
+    m_topControlsHeight = height;
+    m_topControlsShrinkLayoutSize = topControlsShrinkLayoutSize;
     didUpdateTopControls();
 }
 
 void WebViewImpl::didUpdateTopControls()
 {
     WebLocalFrameImpl* localFrameRoot = localFrameRootTemporary();
     if (!localFrameRoot)
         return;
 
     FrameView* view = localFrameRoot->frameView();
     if (!view)
         return;
 
-    float topControlsViewportAdjustment = m_topControlsLayoutHeight - m_topControlsContentOffset;
+    float topControlsViewportAdjustment = 0;
+    if (m_topControlsShrinkLayoutSize)
+        topControlsViewportAdjustment += m_topControlsHeight;
+    topControlsViewportAdjustment -= m_topControlsContentOffset * (m_topControlsOffsetIsNormalized ? m_topControlsHeight : 1);
+
     if (!pinchVirtualViewportEnabled()) {
         // The viewport bounds were adjusted on the compositor by this much due to top controls. Tell
         // the FrameView about it so it can make correct scroll offset clamping decisions during compositor
         // commits.
         view->setTopControlsViewportAdjustment(topControlsViewportAdjustment);
     } else {
         PinchViewport& pinchViewport = page()->frameHost().pinchViewport();
 
         if (pinchViewport.visibleRect().isEmpty())
             return;
@@ skipping 2852 matching lines @@
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 void WebViewImpl::forceNextWebGLContextCreationToFail()
 {
     WebGLRenderingContext::forceNextWebGLContextCreationToFail();
 }
 
 } // namespace blink