GeometryMapper: Support computing visual rects in spaces that are not direct ancestors.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp

 // Copyright 2015 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 "platform/graphics/compositing/PaintArtifactCompositor.h"
 
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/picture_layer.h"
 #include "cc/playback/display_item_list.h"
 #include "cc/playback/display_item_list_settings.h"
 #include "cc/playback/drawing_display_item.h"
 #include "cc/playback/transform_display_item.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/property_tree.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "platform/graphics/paint/ForeignLayerDisplayItem.h"
 #include "platform/graphics/paint/PaintArtifact.h"
+#include "platform/graphics/paint/PropertyTreeState.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebCompositorSupport.h"
 #include "public/platform/WebLayer.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/geometry/size_conversions.h"
@@ skipping 84 matching lines @@
     TransformationMatrix matrix;
     while (currentSpace != targetSpace) {
         TransformationMatrix localMatrix = currentSpace->matrix();
         localMatrix.applyTransformOrigin(currentSpace->origin());
         matrix = localMatrix * matrix;
         currentSpace = currentSpace->parent();
     }
     return gfx::Transform(TransformationMatrix::toSkMatrix44(matrix));
 }
 
-unsigned clipNodeDepth(const ClipPaintPropertyNode* node)
-{
-    unsigned depth = 0;
-    while (node) {
-        depth++;
-        node = node->parent();
-    }
-    return depth;
-}
-
-const ClipPaintPropertyNode* nearestCommonAncestor(const ClipPaintPropertyNode* a, const ClipPaintPropertyNode* b)
-{
-    // Measure both depths.
-    unsigned depthA = clipNodeDepth(a);
-    unsigned depthB = clipNodeDepth(b);
-
-    // Make it so depthA >= depthB.
-    if (depthA < depthB) {
-        std::swap(a, b);
-        std::swap(depthA, depthB);
-    }
-
-    // Make it so depthA == depthB.
-    while (depthA > depthB) {
-        a = a->parent();
-        depthA--;
-    }
-
-    // Walk up until we find the ancestor.
-    while (a != b) {
-        a = a->parent();
-        b = b->parent();
-    }
-    return a;
-}
-
 const TransformPaintPropertyNode* localTransformSpace(const ClipPaintPropertyNode* clip)
 {
     return clip ? clip->localTransformSpace() : nullptr;
 }
 
 scoped_refptr<cc::Layer> createClipLayer(const ClipPaintPropertyNode* node)
 {
     // TODO(jbroman): Handle rounded-rect clips.
     // TODO(jbroman): Handle clips of non-integer size.
     gfx::RectF clipRect = node->clipRect().rect();
@@ skipping 26 matching lines @@
 class ClipLayerManager {
 public:
     ClipLayerManager(cc::Layer* rootLayer)
     {
         m_clipLayers.append(NodeLayerPair(nullptr, rootLayer));
     }
 
     cc::Layer* switchToNewClipLayer(const ClipPaintPropertyNode* clip)
     {
         // Walk up to the nearest common ancestor.
-        const auto* ancestor = nearestCommonAncestor(clip, m_clipLayers.last().first);
+        const auto* ancestor = propertyTreeNearestCommonAncestor<ClipPaintPropertyNode>(clip, m_clipLayers.last().first);
         while (m_clipLayers.last().first != ancestor)
             m_clipLayers.removeLast();
 
         // If the new one was an ancestor, we're done.
         cc::Layer* ancestorClipLayer = m_clipLayers.last().second;
         if (ancestor == clip)
             return ancestorClipLayer;
 
         // Otherwise, we need to build new clip layers.
         // We do this from the bottom up.
@@ skipping 247 matching lines @@
         if (m_extraDataForTestingEnabled)
             m_extraDataForTesting->contentLayers.append(layer);
     }
 
     // Mark the property trees as having been rebuilt.
     host->property_trees()->sequence_number = kPropertyTreeSequenceNumber;
     host->property_trees()->needs_rebuild = false;
 }
 
 } // namespace blink