Send takeover msg from MT to CC using the animation path.

cc/animation/scroll_offset_animations.cc

Index: cc/animation/scroll_offset_animations.cc
diff --git a/cc/animation/scroll_offset_animations.cc b/cc/animation/scroll_offset_animations.cc
index 1dcda6060bb7643a7c156d727c9f19d5814b61b4..04cf954c6f27ad286dafc83fb3f076a9c81c338c 100644
--- a/cc/animation/scroll_offset_animations.cc
+++ b/cc/animation/scroll_offset_animations.cc
@@ -8,38 +8,61 @@
 
 namespace cc {
 
-ScrollOffsetAnimationUpdate::ScrollOffsetAnimationUpdate(Type type,
-                                                         ElementId element_id)
-    : type_(type), element_id_(element_id) {}
+ScrollOffsetAnimationUpdate::ScrollOffsetAnimationUpdate() {}
+
+ScrollOffsetAnimationUpdate::ScrollOffsetAnimationUpdate(ElementId element_id)
+    : element_id_(element_id), takeover_(false) {}
 
 ScrollOffsetAnimations::ScrollOffsetAnimations(AnimationHost* animation_host)
     : animation_host_(animation_host) {}
 
 ScrollOffsetAnimations::~ScrollOffsetAnimations() {}
 
-void ScrollOffsetAnimations::AddUpdate(ScrollOffsetAnimationUpdate update) {
-  queue_.push_back(update);
+ScrollOffsetAnimationUpdate ScrollOffsetAnimations::GetUpdateForElementId(
+    ElementId element_id) const {
+  DCHECK(element_id);
+  auto iter = element_to_update_map_.find(element_id);
+  return iter == element_to_update_map_.end()
+             ? ScrollOffsetAnimationUpdate(element_id)
+             : iter->second;
+}
+
+void ScrollOffsetAnimations::AddAdjustmentUpdate(ElementId element_id,
+                                                 gfx::Vector2dF adjustment) {
+  DCHECK(element_id);
+  ScrollOffsetAnimationUpdate update = GetUpdateForElementId(element_id);
+  update.adjustment_ += adjustment;
+  element_to_update_map_[element_id] = update;
+  animation_host_->SetNeedsCommit();
+}
+
+void ScrollOffsetAnimations::AddTakeoverUpdate(ElementId element_id) {
+  DCHECK(element_id);
+  ScrollOffsetAnimationUpdate update = GetUpdateForElementId(element_id);
+  update.takeover_ = true;
+  element_to_update_map_[element_id] = update;
   animation_host_->SetNeedsCommit();
 }
 
 bool ScrollOffsetAnimations::HasUpdatesForTesting() const {
-  return !queue_.empty();
+  return !element_to_update_map_.empty();
 }
 
 void ScrollOffsetAnimations::PushPropertiesTo(
     ScrollOffsetAnimationsImpl* animations) {
   DCHECK(animations);
-  if (queue_.empty())
+  if (element_to_update_map_.empty())
     return;
 
-  for (auto& update : queue_) {
-    switch (update.type_) {
-      case ScrollOffsetAnimationUpdate::Type::SCROLL_OFFSET_CHANGED:
-        animations->ScrollAnimationApplyAdjustment(update.element_id_,
-                                                   update.adjustment_);
-    }
+  for (auto& kv : element_to_update_map_) {
+    const auto& update = kv.second;
+    if (update.takeover_)
+      animations->ScrollAnimationAbort(true /*needs_completion*/);
+    else
+      animations->ScrollAnimationApplyAdjustment(update.element_id_,
+                                                 update.adjustment_);
   }
-  queue_.clear();
+  element_to_update_map_.clear();
 }
 
 }  // namespace cc