cc: Throttle tile priority updates to once a frame.

cc/layer_tree_host_common.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layer_tree_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/layer.h"
@@ skipping 217 matching lines @@
 {
     // If the opacity is being animated then the opacity on the main thread is unreliable
     // (since the impl thread may be using a different opacity), so it should not be trusted.
     // In particular, it should not cause the subtree to be skipped.
     return !layer->opacity() && !layer->opacityIsAnimating();
 }
 
 // Called on each layer that could be drawn after all information from
 // calcDrawProperties has been updated on that layer.  May have some false
 // positives (e.g. layers get this called on them but don't actually get drawn).
-static inline void markLayerAsUpdated(LayerImpl* layer)
+static inline void updateTilePrioritiesForLayer(LayerImpl* layer)
 {
-    layer->didUpdateTransforms();
+    layer->updateTilePriorities();
 
     // Mask layers don't get this call, so explicitly update them so they can
     // kick off tile rasterization.
     if (layer->maskLayer())
-        layer->maskLayer()->didUpdateTransforms();
+        layer->maskLayer()->updateTilePriorities();
     if (layer->replicaLayer()) {
-        layer->replicaLayer()->didUpdateTransforms();
+        layer->replicaLayer()->updateTilePriorities();
         if (layer->replicaLayer()->maskLayer())
-            layer->replicaLayer()->maskLayer()->didUpdateTransforms();
+            layer->replicaLayer()->maskLayer()->updateTilePriorities();
     }
 }
 
-static inline void markLayerAsUpdated(Layer* layer)
+static inline void updateTilePrioritiesForLayer(Layer* layer)
 {
 }
 
 template<typename LayerType>
 static bool subtreeShouldRenderToSeparateSurface(LayerType* layer, bool axisAlignedWithRespectToParent)
 {
     //
     // A layer and its descendants should render onto a new RenderSurfaceImpl if any of these rules hold:
     //
 
@@ skipping 263 matching lines @@
 }
 
 // Recursively walks the layer tree starting at the given node and computes all the
 // necessary transformations, clipRects, render surfaces, etc.
 template<typename LayerType, typename LayerList, typename RenderSurfaceType>
 static void calculateDrawPropertiesInternal(LayerType* layer, const gfx::Transform& parentMatrix,
     const gfx::Transform& fullHierarchyMatrix, const gfx::Transform& currentScrollCompensationMatrix,
     const gfx::Rect& clipRectFromAncestor, const gfx::Rect& clipRectFromAncestorInDescendantSpace, bool ancestorClipsSubtree,
     RenderSurfaceType* nearestAncestorThatMovesPixels, LayerList& renderSurfaceLayerList, LayerList& layerList,
     LayerSorter* layerSorter, int maxTextureSize, float deviceScaleFactor, float pageScaleFactor, bool subtreeCanUseLCDText,
-    gfx::Rect& drawableContentRectOfSubtree)
+    gfx::Rect& drawableContentRectOfSubtree, bool updateTilePriorities)
 {
     // This function computes the new matrix transformations recursively for this
     // layer and all its descendants. It also computes the appropriate render surfaces.
     // Some important points to remember:
     //
     // 0. Here, transforms are notated in Matrix x Vector order, and in words we describe what
     //    the transform does from left to right.
     //
     // 1. In our terminology, the "layer origin" refers to the top-left corner of a layer, and the
     //    positive Y-axis points downwards. This interpretation is valid because the orthographic
@@ skipping 325 matching lines @@
 
     gfx::Transform nextScrollCompensationMatrix = computeScrollCompensationMatrixForChildren(layer, parentMatrix, currentScrollCompensationMatrix);;
 
     gfx::Rect accumulatedDrawableContentRectOfChildren;
     for (size_t i = 0; i < layer->children().size(); ++i) {
         LayerType* child = LayerTreeHostCommon::getChildAsRawPtr(layer->children(), i);
         gfx::Rect drawableContentRectOfChildSubtree;
         calculateDrawPropertiesInternal<LayerType, LayerList, RenderSurfaceType>(child, sublayerMatrix, nextHierarchyMatrix, nextScrollCompensationMatrix,
                                                                                  clipRectForSubtree, clipRectForSubtreeInDescendantSpace, subtreeShouldBeClipped, nearestAncestorThatMovesPixels,
                                                                                  renderSurfaceLayerList, descendants, layerSorter, maxTextureSize, deviceScaleFactor, pageScaleFactor,
-                                                                                 subtreeCanUseLCDText, drawableContentRectOfChildSubtree);
+                                                                                 subtreeCanUseLCDText, drawableContentRectOfChildSubtree, updateTilePriorities);
         if (!drawableContentRectOfChildSubtree.IsEmpty()) {
             accumulatedDrawableContentRectOfChildren.Union(drawableContentRectOfChildSubtree);
             if (child->renderSurface())
                 descendants.push_back(child);
         }
     }
 
     if (layer->renderSurface() && !isRootLayer(layer) && !layer->renderSurface()->layerList().size()) {
         removeSurfaceForEarlyExit(layer, renderSurfaceLayerList);
         return;
@@ skipping 79 matching lines @@
             // Compute the replica's "originTransform" that maps from the replica's origin space to the target surface origin space.
             gfx::Transform replicaOriginTransform = layer->renderSurface()->drawTransform() * surfaceOriginToReplicaOriginTransform;
             renderSurface->setReplicaDrawTransform(replicaOriginTransform);
 
             // Compute the replica's "screenSpaceTransform" that maps from the replica's origin space to the screen's origin space.
             gfx::Transform replicaScreenSpaceTransform = layer->renderSurface()->screenSpaceTransform() * surfaceOriginToReplicaOriginTransform;
             renderSurface->setReplicaScreenSpaceTransform(replicaScreenSpaceTransform);
         }
     }
 
-    markLayerAsUpdated(layer);
+    if (updateTilePriorities)
+        updateTilePrioritiesForLayer(layer);
 
     // If neither this layer nor any of its children were added, early out.
     if (sortingStartIndex == descendants.size())
         return;
 
     // If preserves-3d then sort all the descendants in 3D so that they can be
     // drawn from back to front. If the preserves-3d property is also set on the parent then
     // skip the sorting as the parent will sort all the descendants anyway.
     if (layerSorter && descendants.size() && layer->preserves3D() && (!layer->parent() || !layer->parent()->preserves3D()))
         sortLayers(descendants.begin() + sortingStartIndex, descendants.end(), layerSorter);
@@ skipping 11 matching lines @@
 {
     gfx::Rect totalDrawableContentRect;
     gfx::Transform identityMatrix;
     gfx::Transform deviceScaleTransform;
     deviceScaleTransform.Scale(deviceScaleFactor, deviceScaleFactor);
     std::vector<scoped_refptr<Layer> > dummyLayerList;
 
     // The root layer's renderSurface should receive the deviceViewport as the initial clipRect.
     bool subtreeShouldBeClipped = true;
     gfx::Rect deviceViewportRect(gfx::Point(), deviceViewportSize);
+    bool updateTilePriorities = false;
 
     // This function should have received a root layer.
     DCHECK(isRootLayer(rootLayer));
 
     preCalculateMetaInformation<Layer>(rootLayer);
     calculateDrawPropertiesInternal<Layer, std::vector<scoped_refptr<Layer> >, RenderSurface>(
         rootLayer, deviceScaleTransform, identityMatrix, identityMatrix,
         deviceViewportRect, deviceViewportRect, subtreeShouldBeClipped, 0, renderSurfaceLayerList,
         dummyLayerList, 0, maxTextureSize,
-        deviceScaleFactor, pageScaleFactor, canUseLCDText, totalDrawableContentRect);
+        deviceScaleFactor, pageScaleFactor, canUseLCDText, totalDrawableContentRect,
+        updateTilePriorities);
 
     // The dummy layer list should not have been used.
     DCHECK(dummyLayerList.size() == 0);
     // A root layer renderSurface should always exist after calculateDrawProperties.
     DCHECK(rootLayer->renderSurface());
 }
 
-void LayerTreeHostCommon::calculateDrawProperties(LayerImpl* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, int maxTextureSize, bool canUseLCDText, std::vector<LayerImpl*>& renderSurfaceLayerList)
+void LayerTreeHostCommon::calculateDrawProperties(LayerImpl* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, int maxTextureSize, bool canUseLCDText, std::vector<LayerImpl*>& renderSurfaceLayerList, bool updateTilePriorities)
 {
     gfx::Rect totalDrawableContentRect;
     gfx::Transform identityMatrix;
     gfx::Transform deviceScaleTransform;
     deviceScaleTransform.Scale(deviceScaleFactor, deviceScaleFactor);
     std::vector<LayerImpl*> dummyLayerList;
     LayerSorter layerSorter;
     
     // The root layer's renderSurface should receive the deviceViewport as the initial clipRect.
     bool subtreeShouldBeClipped = true;
     gfx::Rect deviceViewportRect(gfx::Point(), deviceViewportSize);
 
     // This function should have received a root layer.
     DCHECK(isRootLayer(rootLayer));
 
     preCalculateMetaInformation<LayerImpl>(rootLayer);
     calculateDrawPropertiesInternal<LayerImpl, std::vector<LayerImpl*>, RenderSurfaceImpl>(
         rootLayer, deviceScaleTransform, identityMatrix, identityMatrix,
         deviceViewportRect, deviceViewportRect, subtreeShouldBeClipped, 0, renderSurfaceLayerList,
         dummyLayerList, &layerSorter, maxTextureSize,
-        deviceScaleFactor, pageScaleFactor, canUseLCDText, totalDrawableContentRect);
+        deviceScaleFactor, pageScaleFactor, canUseLCDText, totalDrawableContentRect,
+        updateTilePriorities);
 
     // The dummy layer list should not have been used.
     DCHECK(dummyLayerList.size() == 0);
     // A root layer renderSurface should always exist after calculateDrawProperties.
     DCHECK(rootLayer->renderSurface());
 }
 
 static bool pointHitsRect(const gfx::PointF& screenSpacePoint, const gfx::Transform& localSpaceToScreenSpaceTransform, gfx::RectF localSpaceRect)
 {
     // If the transform is not invertible, then assume that this point doesn't hit this rect.
@@ skipping 119 matching lines @@
 
   // At this point, we think the point does hit the touch event handler region on the layer, but we need to walk up
   // the parents to ensure that the layer was not clipped in such a way that the
   // hit point actually should not hit the layer.
   if (pointIsClippedBySurfaceOrClipRect(screenSpacePoint, layerImpl))
      return false;
 
   return true;
 }
 }  // namespace cc