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 7ce1bf147f8e5edeb86505d3ab7e69af94be03d9..eb83265a864faa1aaa9d7df3896612a164c5a385 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -37,6 +37,7 @@
 #include "cc/software_renderer.h"
 #include "cc/solid_color_draw_quad.h"
 #include "cc/texture_uploader.h"
+#include "cc/top_controls_manager.h"
 #include "cc/util.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/vector2d_conversions.h"
@@ -235,6 +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.topControlsHeightPx);
+
     // LTHI always has an active tree.
     m_activeTree = LayerTreeImpl::create(this);
 }
@@ -318,6 +322,8 @@ 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()
@@ -418,6 +424,8 @@ void LayerTreeHostImpl::updateDrawProperties()
     }
 
     activeTree()->UpdateDrawProperties();
+    if (m_topControlsManager)
+      m_topControlsManager->UpdateDrawPositions();

[enne (OOO), 2013/01/08 06:23:05]

How is this supposed to work? You update the active tree and *then* update impl
transforms on part of the tree via UpdateDrawPositions.  So, now the layer tree
transforms aren't up to date anymore.

[Ted C, 2013/01/08 18:17:33]

Why wouldn't the transforms be up to date?  The layer tree doesn't seem to hold
onto anything it just updates the containing layers.  This should just be
additive work on top of those previously computed transforms.

[enne (OOO), 2013/01/08 18:23:50]

Because the implTransform on a layer is an input to its drawTransform and
screenSpaceTransform.  If you set it post-calcDrawProperties, you're changing an
input after the output has been calculated.

[Ted C, 2013/01/08 18:32:42]

Ah ha...that certainly wasn't my intention.  When I started this whole patch, I
had my call to this prior to the call to calcDrawProperties, but then it got
factored out into the activeTree()->UpdateDrawProperties() and I guess I merged
it badly.  This certainly can be moved above the above line (and I tested it and
it works fine).

     if (pendingTree())
       pendingTree()->UpdateDrawProperties();
 
@@ -872,6 +880,10 @@ 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;
 }
@@ -998,6 +1010,11 @@ static LayerImpl* findScrollLayerForContentLayer(LayerImpl* layerImpl)
     return 0;
 }
 
+LayerTreeImpl* LayerTreeHostImpl::activeTree()
+{
+    return m_activeTree.get();
+}
+
 void LayerTreeHostImpl::createPendingTree()
 {
     CHECK(!m_pendingTree);
@@ -1188,6 +1205,11 @@ void LayerTreeHostImpl::updateMaxScrollOffset()
         pendingTree()->UpdateMaxScrollOffset();
 }
 
+void LayerTreeHostImpl::setNeedsUpdateDrawProperties()
+{
+    m_needsUpdateDrawProperties = true;
+}
+
 void LayerTreeHostImpl::setNeedsRedraw()
 {
     m_client->setNeedsRedrawOnImplThread();
@@ -1203,6 +1225,9 @@ InputHandlerClient::ScrollStatus LayerTreeHostImpl::scrollBegin(gfx::Point viewp
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::scrollBegin");
 
+    if (m_topControlsManager)
+        m_topControlsManager->ScrollBegin();
+
     DCHECK(!currentlyScrollingLayer());
     clearCurrentlyScrollingLayer();
 
@@ -1335,6 +1360,9 @@ 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);
@@ -1379,6 +1407,8 @@ void LayerTreeHostImpl::clearCurrentlyScrollingLayer()
 
 void LayerTreeHostImpl::scrollEnd()
 {
+    if (m_topControlsManager)
+        m_topControlsManager->ScrollEnd();
     clearCurrentlyScrollingLayer();
 }