Revert of Split RootScrollerController into top-document and child-document classes

third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp

Index: third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp b/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
index 52aed2ef694a61823640ae159c1ab72b35b0bfb6..798465b93aa4be02018919910ea6f1600ba52d95 100644
--- a/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
+++ b/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
@@ -8,7 +8,13 @@
 #include "core/dom/Element.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
+#include "core/frame/TopControls.h"
+#include "core/frame/VisualViewport.h"
 #include "core/layout/LayoutBox.h"
+#include "core/page/ChromeClient.h"
+#include "core/page/Page.h"
+#include "core/page/scrolling/OverscrollController.h"
+#include "core/page/scrolling/ViewportScrollCallback.h"
 #include "core/paint/PaintLayerScrollableArea.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/scroll/ScrollableArea.h"
@@ -19,87 +25,7 @@
 
 namespace {
 
-bool fillsViewport(const Element& element)
-{
-    DCHECK(element.layoutObject());
-    DCHECK(element.layoutObject()->isBox());
-
-    LayoutObject* layoutObject = element.layoutObject();
-
-    // TODO(bokan): Broken for OOPIF.
-    Document& topDocument = element.document().topDocument();
-
-    Vector<FloatQuad> quads;
-    layoutObject->absoluteQuads(quads);
-    DCHECK_EQ(quads.size(), 1u);
-
-    if (!quads[0].isRectilinear())
-        return false;
-
-    LayoutRect boundingBox(quads[0].boundingBox());
-
-    return boundingBox.location() == LayoutPoint::zero()
-        && boundingBox.size() == topDocument.layoutViewItem().size();
-}
-
-} // namespace
-
-// static
-RootScrollerController* RootScrollerController::create(Document& document)
-{
-    return new RootScrollerController(document);
-}
-
-RootScrollerController::RootScrollerController(Document& document)
-    : m_document(&document)
-{
-}
-
-DEFINE_TRACE(RootScrollerController)
-{
-    visitor->trace(m_document);
-    visitor->trace(m_rootScroller);
-    visitor->trace(m_effectiveRootScroller);
-}
-
-void RootScrollerController::set(Element* newRootScroller)
-{
-    m_rootScroller = newRootScroller;
-    updateEffectiveRootScroller();
-}
-
-Element* RootScrollerController::get() const
-{
-    return m_rootScroller;
-}
-
-Element* RootScrollerController::effectiveRootScroller() const
-{
-    return m_effectiveRootScroller;
-}
-
-void RootScrollerController::didUpdateLayout()
-{
-    updateEffectiveRootScroller();
-}
-
-void RootScrollerController::updateEffectiveRootScroller()
-{
-    bool rootScrollerValid =
-        m_rootScroller && isValidRootScroller(*m_rootScroller);
-
-    Element* newEffectiveRootScroller = rootScrollerValid
-        ? m_rootScroller.get()
-        : defaultEffectiveRootScroller();
-
-    if (m_effectiveRootScroller == newEffectiveRootScroller)
-        return;
-
-    m_effectiveRootScroller = newEffectiveRootScroller;
-}
-
-ScrollableArea* RootScrollerController::scrollableAreaFor(
-    const Element& element) const
+ScrollableArea* scrollableAreaFor(const Element& element)
 {
     if (!element.layoutObject() || !element.layoutObject()->isBox())
         return nullptr;
@@ -117,7 +43,30 @@
         box->getScrollableArea());
 }
 
-bool RootScrollerController::isValidRootScroller(const Element& element) const
+bool fillsViewport(const Element& element)
+{
+    DCHECK(element.layoutObject());
+    DCHECK(element.layoutObject()->isBox());
+
+    LayoutObject* layoutObject = element.layoutObject();
+
+    // TODO(bokan): Broken for OOPIF.
+    Document& topDocument = element.document().topDocument();
+
+    Vector<FloatQuad> quads;
+    layoutObject->absoluteQuads(quads);
+    DCHECK_EQ(quads.size(), 1u);
+
+    if (!quads[0].isRectilinear())
+        return false;
+
+    LayoutRect boundingBox(quads[0].boundingBox());
+
+    return boundingBox.location() == LayoutPoint::zero()
+        && boundingBox.size() == topDocument.layoutViewItem().size();
+}
+
+bool isValidRootScroller(const Element& element)
 {
     if (!element.layoutObject())
         return false;
@@ -131,12 +80,122 @@
     return true;
 }
 
+} // namespace
+
+RootScrollerController::RootScrollerController(Document& document)
+    : m_document(&document)
+{
+}
+
+DEFINE_TRACE(RootScrollerController)
+{
+    visitor->trace(m_document);
+    visitor->trace(m_viewportApplyScroll);
+    visitor->trace(m_rootScroller);
+    visitor->trace(m_effectiveRootScroller);
+    visitor->trace(m_currentViewportApplyScrollHost);
+}
+
+void RootScrollerController::set(Element* newRootScroller)
+{
+    m_rootScroller = newRootScroller;
+    updateEffectiveRootScroller();
+}
+
+Element* RootScrollerController::get() const
+{
+    return m_rootScroller;
+}
+
+Element* RootScrollerController::effectiveRootScroller() const
+{
+    return m_effectiveRootScroller;
+}
+
+void RootScrollerController::didUpdateLayout()
+{
+    updateEffectiveRootScroller();
+}
+
+void RootScrollerController::updateEffectiveRootScroller()
+{
+    bool rootScrollerValid =
+        m_rootScroller && isValidRootScroller(*m_rootScroller);
+
+    Element* newEffectiveRootScroller = rootScrollerValid
+        ? m_rootScroller.get()
+        : defaultEffectiveRootScroller();
+
+    if (m_effectiveRootScroller == newEffectiveRootScroller)
+        return;
+
+    m_effectiveRootScroller = newEffectiveRootScroller;
+
+    if (m_document->isInMainFrame())
+        setViewportApplyScrollOnRootScroller();
+}
+
+void RootScrollerController::setViewportApplyScrollOnRootScroller()
+{
+    DCHECK(m_document->isInMainFrame());
+
+    if (!m_viewportApplyScroll || !m_effectiveRootScroller)
+        return;
+
+    ScrollableArea* targetScroller =
+        scrollableAreaFor(*m_effectiveRootScroller);
+
+    if (!targetScroller)
+        return;
+
+    if (m_currentViewportApplyScrollHost)
+        m_currentViewportApplyScrollHost->removeApplyScroll();
+
+    // Use disable-native-scroll since the ViewportScrollCallback needs to
+    // apply scroll actions both before (TopControls) and after (overscroll)
+    // scrolling the element so it will apply scroll to the element itself.
+    m_effectiveRootScroller->setApplyScroll(
+        m_viewportApplyScroll, "disable-native-scroll");
+
+    m_currentViewportApplyScrollHost = m_effectiveRootScroller;
+
+    // Ideally, scroll customization would pass the current element to scroll to
+    // the apply scroll callback but this doesn't happen today so we set it
+    // through a back door here. This is also needed by the
+    // ViewportScrollCallback to swap the target into the layout viewport
+    // in RootFrameViewport.
+    m_viewportApplyScroll->setScroller(targetScroller);
+}
+
 void RootScrollerController::didUpdateCompositing()
 {
+    FrameHost* frameHost = m_document->frameHost();
+
+    // Let the compositor-side counterpart know about this change.
+    if (frameHost && m_document->isInMainFrame())
+        frameHost->chromeClient().registerViewportLayers();
 }
 
 void RootScrollerController::didAttachDocument()
 {
+    if (!m_document->isInMainFrame())
+        return;
+
+    FrameHost* frameHost = m_document->frameHost();
+    FrameView* frameView = m_document->view();
+
+    if (!frameHost || !frameView)
+        return;
+
+    RootFrameViewport* rootFrameViewport = frameView->getRootFrameViewport();
+    DCHECK(rootFrameViewport);
+
+    m_viewportApplyScroll = ViewportScrollCallback::create(
+        &frameHost->topControls(),
+        &frameHost->overscrollController(),
+        *rootFrameViewport);
+
+    updateEffectiveRootScroller();
 }
 
 GraphicsLayer* RootScrollerController::rootScrollerLayer()
@@ -161,13 +220,10 @@
 bool RootScrollerController::isViewportScrollCallback(
     const ScrollStateCallback* callback) const
 {
-    // TopDocumentRootScrollerController must override this method to actually
-    // do the comparison.
-    DCHECK(!m_document->isInMainFrame());
-
-    RootScrollerController* topDocumentController =
-        m_document->topDocument().rootScrollerController();
-    return topDocumentController->isViewportScrollCallback(callback);
+    if (!callback)
+        return false;
+
+    return callback == m_viewportApplyScroll.get();
 }
 
 Element* RootScrollerController::defaultEffectiveRootScroller()