Adjust maximum scroll bounds on FrameView to account for top controls. (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 396 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)
 {
     Page::PageClients pageClients;
     pageClients.chromeClient = &m_chromeClientImpl;
     pageClients.contextMenuClient = &m_contextMenuClientImpl;
     pageClients.editorClient = &m_editorClientImpl;
     pageClients.dragClient = &m_dragClientImpl;
     pageClients.inspectorClient = &m_inspectorClientImpl;
     pageClients.backForwardClient = &m_backForwardClientImpl;
     pageClients.spellCheckerClient = &m_spellCheckerClientImpl;
     pageClients.storageClient = &m_storageClientImpl;
@@ skipping 1232 matching lines @@
     if (page()->inspectorController().deviceEmulationEnabled()) {
         if (Document* document = localFrameRootTemporary()->frame()->document())
             document->mediaQueryAffectingValueChanged();
     }
 }
 
 void WebViewImpl::setTopControlsContentOffset(float offset)
 {
     m_topControlsContentOffset = offset;
     m_layerTreeView->setTopControlsContentOffset(offset);
+    didUpdateTopControls();
+}
+
+void WebViewImpl::setTopControlsLayoutHeight(float height)
+{
+    m_topControlsLayoutHeight = height;
+    didUpdateTopControls();
+}
+
+void WebViewImpl::didUpdateTopControls()
+{
+    FrameView* view = localFrameRootTemporary()->frameView();
+    if (!view)
+        return;
+
+    // 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.
+    float topControlsViewportAdjustment = m_topControlsContentOffset - m_topControlsLayoutHeight;
+    view->setTopControlsViewportAdjustment(topControlsViewportAdjustment);

[bokan, 2014/09/09 23:14:19]

There's also a Chromium-side patch that just calls setTopControlsLayoutHeight in
RenderWidget::Resize. I'll land this patch first with this line commented out so
it doesn't change behaviour.

[aelias_OOO_until_Jul13, 2014/09/10 01:57:29]

If you prefer, you could also avoid the third patch by making this conditional
on pinch viewport mode being active, as nobody cares about temporary breakage
there yet.

[bokan, 2014/09/10 13:51:52]

One liners like that are easy enough to land + I'd have to change up the test.
Side-note: can I just TBR-commit the patch to uncomment?

[aelias_OOO_until_Jul13, 2014/09/10 15:51:45]

Yes, feel free to TBR that and mention I preapproved that here.

 }
 
 void WebViewImpl::resize(const WebSize& newSize)
 {
     if (m_shouldAutoResize || m_size == newSize)
         return;
 
     FrameView* view = localFrameRootTemporary()->frameView();
     if (!view)
         return;
@@ skipping 2611 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink