Add support for calculating the position of the top controls in the cc layer.

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index 685effb47e7a80462231a78598cc5a6abaa6a54b..db7977a04cf13804164287a9dcce11177f0aeaf0 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -236,6 +236,9 @@ LayerTreeHostImpl::LayerTreeHostImpl(const LayerTreeSettings& settings, LayerTre
     DCHECK(m_proxy->isImplThread());
     didVisibilityChange(this, m_visible);
 
+    if (settings.calculateTopControlsPosition)
+        m_topControlsManager = TopControlsManager::Create(this, settings.topControlsHeight);
+
     // TODO(nduca): For now, assume we have an active tree. This will be removed
     // in future patches.
     m_activeTree = LayerTreeImpl::create(this);
@@ -306,6 +309,8 @@ void LayerTreeHostImpl::animate(base::TimeTicks monotonicTime, base::Time wallCl
     animatePageScale(monotonicTime);
     animateLayers(monotonicTime, wallClockTime);
     animateScrollbars(monotonicTime);
+    if (m_topControlsManager)
+        m_topControlsManager->Animate(monotonicTime);
 }
 
 void LayerTreeHostImpl::manageTiles()
@@ -404,6 +409,8 @@ void LayerTreeHostImpl::updateDrawProperties()
     {
         TRACE_EVENT0("cc", "LayerTreeHostImpl::calcDrawEtc");
         float pageScaleFactor = m_pinchZoomViewport.pageScaleFactor();
+        if (m_topControlsManager)
+            m_topControlsManager->UpdateDrawPositions();
         LayerTreeHostCommon::calculateDrawProperties(rootLayer(), deviceViewportSize(), m_deviceScaleFactor, pageScaleFactor, rendererCapabilities().maxTextureSize, m_settings.canUseLCDText, m_renderSurfaceLayerList);
     }
 }
@@ -889,6 +896,10 @@ CompositorFrameMetadata LayerTreeHostImpl::makeCompositorFrameMetadata() const
         metadata.root_scroll_offset.Scale(1 / m_pinchZoomViewport.pageScaleFactor());
         metadata.root_layer_size.Scale(1 / m_pinchZoomViewport.pageScaleFactor());
     }
+    if (m_topControlsManager) {
+        metadata.location_bar_offset = gfx::Vector2dF(0.f, m_topControlsManager->controls_top_offset());
+        metadata.content_offset = gfx::Vector2dF(0.f, m_topControlsManager->content_top_offset());
+    }
 
     return metadata;
 }
@@ -1016,6 +1027,11 @@ static LayerImpl* findScrollLayerForContentLayer(LayerImpl* layerImpl)
     return 0;
 }
 
+LayerTreeImpl* LayerTreeHostImpl::activeTree()
+{
+    return m_activeTree.get();
+}
+
 void LayerTreeHostImpl::setRootLayer(scoped_ptr<LayerImpl> layer)
 {
     m_activeTree->SetRootLayer(layer.Pass());
@@ -1211,6 +1227,11 @@ void LayerTreeHostImpl::updateMaxScrollOffset()
     rootScrollLayer()->setMaxScrollOffset(gfx::ToFlooredVector2d(maxScroll));
 }
 
+void LayerTreeHostImpl::setNeedsUpdateDrawProperties()
+{
+    m_needsUpdateDrawProperties = true;
+}
+
 void LayerTreeHostImpl::setNeedsRedraw()
 {
     m_client->setNeedsRedrawOnImplThread();
@@ -1226,6 +1247,9 @@ InputHandlerClient::ScrollStatus LayerTreeHostImpl::scrollBegin(gfx::Point viewp
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::scrollBegin");
 
+    if (m_topControlsManager)
+        m_topControlsManager->ScrollBegin();
+
     DCHECK(!currentlyScrollingLayer());
     clearCurrentlyScrollingLayer();
 
@@ -1353,6 +1377,9 @@ bool LayerTreeHostImpl::scrollBy(const gfx::Point& viewportPoint,
         if (m_settings.pageScalePinchZoomEnabled && layerImpl == rootScrollLayer())
             viewport = &m_pinchZoomViewport;
         gfx::Vector2dF appliedDelta;
+        if (m_topControlsManager && layerImpl == rootScrollLayer())
+            pendingDelta = m_topControlsManager->ScrollBy(pendingDelta);
+
         if (m_scrollDeltaIsInViewportSpace) {
             float scaleFromViewportToScreenSpace = m_deviceScaleFactor;
             appliedDelta = scrollLayerWithViewportSpaceDelta(viewport, *layerImpl, scaleFromViewportToScreenSpace, viewportPoint, pendingDelta);
@@ -1397,6 +1424,8 @@ void LayerTreeHostImpl::clearCurrentlyScrollingLayer()
 
 void LayerTreeHostImpl::scrollEnd()
 {
+    if (m_topControlsManager)
+        m_topControlsManager->ScrollEnd();
     clearCurrentlyScrollingLayer();
 }