Fix an issue that fullscreen layer is scrollable

Source/core/page/scrolling/ScrollingCoordinator.cpp

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "core/page/scrolling/ScrollingCoordinator.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "core/dom/Document.h"
+#include "core/dom/FullscreenElementStack.h"
 #include "core/dom/Node.h"
 #include "core/dom/WheelController.h"
 #include "core/html/HTMLElement.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
 #include "core/page/Page.h"
-#include "core/frame/Settings.h"
+#include "core/plugins/PluginView.h"
+#include "core/rendering/RenderGeometryMap.h"
+#include "core/rendering/RenderView.h"
+#include "core/rendering/compositing/CompositedLayerMapping.h"
+#include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "platform/TraceEvent.h"
 #include "platform/exported/WebScrollbarImpl.h"
 #include "platform/exported/WebScrollbarThemeGeometryNative.h"
 #include "platform/geometry/Region.h"
 #include "platform/geometry/TransformState.h"
 #include "platform/graphics/GraphicsLayer.h"
 #if OS(MACOSX)
 #include "platform/mac/ScrollAnimatorMac.h"
 #endif
 #include "platform/scroll/ScrollAnimator.h"
 #include "platform/scroll/ScrollbarTheme.h"
-#include "core/plugins/PluginView.h"
-#include "core/rendering/RenderGeometryMap.h"
-#include "core/rendering/RenderView.h"
-#include "core/rendering/compositing/CompositedLayerMapping.h"
-#include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebCompositorSupport.h"
 #include "public/platform/WebLayerPositionConstraint.h"
 #include "public/platform/WebScrollbarLayer.h"
 #include "public/platform/WebScrollbarThemeGeometry.h"
 #include "public/platform/WebScrollbarThemePainter.h"
 #include "wtf/text/StringBuilder.h"
 
 using blink::WebLayer;
 using blink::WebLayerPositionConstraint;
@@ skipping 88 matching lines @@
     FrameView* frameView = m_page->mainFrame()->view();
     bool frameIsScrollable = frameView && frameView->isScrollable();
     if (m_shouldScrollOnMainThreadDirty || m_wasFrameScrollable != frameIsScrollable) {
         setShouldUpdateScrollLayerPositionOnMainThread(mainThreadScrollingReasons());
         m_shouldScrollOnMainThreadDirty = false;
     }
     m_wasFrameScrollable = frameIsScrollable;
 
     // The mainFrame view doesn't get included in the FrameTree below, so we
     // update its size separately.
-    if (WebLayer* scrollingWebLayer = frameView ? toWebLayer(frameView->layerForScrolling()) : 0)
+    if (WebLayer* scrollingWebLayer = frameView ? toWebLayer(frameView->layerForScrolling()) : 0) {
         scrollingWebLayer->setBounds(frameView->contentsSize());
+        // If there is a fullscreen element, set the scroll clip layer to 0 so main frame won't scroll.
+        // TODO(qinmin): find a better way to handle the fullscreen case.

[aelias_OOO_until_Jul13, 2014/03/19 01:02:21]

nit: please remove this TODO, it doesn't provide useful information and this
approach may be OK for a while.

[qinmin, 2014/03/19 02:26:39]

Done.

+        Element* fullscreenElement = FullscreenElementStack::fullscreenElementFrom(*(m_page->mainFrame()->document()));
+        if (fullscreenElement)
+            scrollingWebLayer->setScrollClipLayer(0);

[aelias_OOO_until_Jul13, 2014/03/19 01:02:21]

Blink style is to use "nullptr".

[qinmin, 2014/03/19 02:26:39]

I think nullptr was used for smart pointers, not for dumb pointers like here
unless we change the WebLayer interface.

+        else
+            scrollingWebLayer->setScrollClipLayer(toWebLayer(frameView->layerForContainer()));
+    }
 
     const FrameTree& tree = m_page->mainFrame()->tree();
     for (const LocalFrame* child = tree.firstChild(); child; child = child->tree().nextSibling()) {
         if (WebLayer* scrollLayer = toWebLayer(child->view()->layerForScrolling()))
             scrollLayer->setBounds(child->view()->contentsSize());
     }
 }
 
 void ScrollingCoordinator::setLayerIsContainerForFixedPositionLayers(GraphicsLayer* layer, bool enable)
 {
@@ skipping 768 matching lines @@
     bool frameIsScrollable = frameView && frameView->isScrollable();
     if (frameIsScrollable != m_wasFrameScrollable)
         return true;
 
     if (WebLayer* scrollLayer = frameView ? toWebLayer(frameView->layerForScrolling()) : 0)
         return blink::WebSize(frameView->contentsSize()) != scrollLayer->bounds();
     return false;
 }
 
 } // namespace WebCore