[NOT FOR REVIEW]

cc/trees/property_tree.cc

Index: cc/trees/property_tree.cc
diff --git a/cc/trees/property_tree.cc b/cc/trees/property_tree.cc
index 9850577ff4ed778e9f6fd3ce8eb87e7cd57ef092..6df4f353ea72db1fcc7ca328c44732de3d5101cd 100644
--- a/cc/trees/property_tree.cc
+++ b/cc/trees/property_tree.cc
@@ -1092,6 +1092,12 @@ gfx::RectF ClipTree::ViewportClip() const {
   return Node(kViewportNodeId)->clip;
 }
 
+void ClipTree::set_needs_update(bool needs_update) {
+  if (needs_update && !needs_update_)
+    property_trees()->UpdateClipTreeUpdateNumber();
+  needs_update_ = needs_update;
+}
+
 bool ClipTree::operator==(const ClipTree& other) const {
   return PropertyTree::operator==(other);
 }
@@ -1537,7 +1543,7 @@ gfx::ScrollOffset ScrollTree::ClampScrollOffsetToLimits(
 }
 
 PropertyTreesCachedData::PropertyTreesCachedData()
-    : transform_tree_update_number(0) {
+    : transform_tree_update_number(0), clip_tree_update_number(0) {
   animation_scales.clear();
 }
 
@@ -2002,6 +2008,58 @@ DrawTransformData& PropertyTrees::FetchDrawTransformsDataFromCache(
   return data;
 }
 
+int PropertyTrees::ClipRectCacheId(int clip_id, int target_id) const {
+  auto& cached_clips = cached_data_.clip_rects[clip_id];
+  for (size_t i = 0; i < cached_clips.size(); i++) {
+    if (cached_clips[i].target_id == target_id &&
+        cached_clips[i].update_number == cached_data_.clip_tree_update_number)
+      return static_cast<int>(i);
+  }
+  return -1;
+}
+
+ConditionalClip& PropertyTrees::FetchClipRectFromCache(int clip_id,
+                                                       int target_id,
+                                                       int cache_index) const {
+  DCHECK_GE(cache_index, 0);
+  DCHECK_NE(ClipRectCacheId(clip_id, target_id), -1);
+  DCHECK_EQ(cached_data_.clip_rects[clip_id][cache_index].update_number,
+            cached_data_.clip_tree_update_number);
+  return cached_data_.clip_rects[clip_id][cache_index].clip;
+}
+
+void PropertyTrees::AddToClipRectCache(int clip_id,
+                                       int target_id,
+                                       const ConditionalClip& clip) {
+  auto& cached_clips = cached_data_.clip_rects[clip_id];
+
+  if (cached_clips.size() > 1 || cached_clips.back().target_id != -1) {
+    cached_clips.push_back(ClipRectData());
+  }
+
+  ClipRectData& data = cached_clips.back();
+  data.update_number = cached_data_.clip_tree_update_number;
+  data.target_id = target_id;
+  data.clip = clip;
+}
+
+bool PropertyTrees::IsInVisibleRectCache(int clip_id) const {
+  return cached_data_.visible_rects[clip_id].update_number ==
+         cached_data_.clip_tree_update_number;
+}
+
+gfx::RectF PropertyTrees::FetchVisibleRectFromCache(int clip_id) const {
+  DCHECK_EQ(cached_data_.visible_rects[clip_id].update_number,
+            cached_data_.clip_tree_update_number);
+  return cached_data_.visible_rects[clip_id].visible_rect;
+}
+
+void PropertyTrees::AddToVisibleRectCache(int clip_id, const gfx::RectF& rect) {
+  auto& visible_rect_data = cached_data_.visible_rects[clip_id];
+  visible_rect_data.update_number = cached_data_.clip_tree_update_number;
+  visible_rect_data.visible_rect = rect;
+}
+
 DrawTransforms& PropertyTrees::GetDrawTransforms(int transform_id,
                                                  int effect_id) const {
   const EffectNode* effect_node = effect_tree.Node(effect_id);
@@ -2060,16 +2118,25 @@ DrawTransforms& PropertyTrees::GetDrawTransforms(int transform_id,
 
 void PropertyTrees::ResetCachedData() {
   cached_data_.transform_tree_update_number = 0;
+  cached_data_.clip_tree_update_number = 0;
   cached_data_.animation_scales = std::vector<AnimationScaleData>(
       transform_tree.nodes().size(), AnimationScaleData());
   cached_data_.draw_transforms = std::vector<std::vector<DrawTransformData>>(
       transform_tree.nodes().size(), std::vector<DrawTransformData>(1));
+  cached_data_.clip_rects = std::vector<std::vector<ClipRectData>>(
+      clip_tree.nodes().size(), std::vector<ClipRectData>(1));
+  cached_data_.visible_rects =
+      std::vector<VisibleRectData>(clip_tree.nodes().size());
 }
 
 void PropertyTrees::UpdateTransformTreeUpdateNumber() {
   cached_data_.transform_tree_update_number++;
 }
 
+void PropertyTrees::UpdateClipTreeUpdateNumber() {
+  cached_data_.clip_tree_update_number++;
+}
+
 gfx::Transform PropertyTrees::ToScreenSpaceTransformWithoutSurfaceContentsScale(
     int transform_id,
     int effect_id) const {