Store non-fast scrollable regions on ScrollNode

cc/trees/scroll_node.cc

Index: cc/trees/scroll_node.cc
diff --git a/cc/trees/scroll_node.cc b/cc/trees/scroll_node.cc
index 18b5d42d974b2515f92aa940c69d882f784fe73c..14431e645508d39524a381e62e605aa3b247f70f 100644
--- a/cc/trees/scroll_node.cc
+++ b/cc/trees/scroll_node.cc
@@ -19,7 +19,6 @@ ScrollNode::ScrollNode()
       scrollable(false),
       main_thread_scrolling_reasons(
           MainThreadScrollingReason::kNotScrollingOnMain),
-      contains_non_fast_scrollable_region(false),
       max_scroll_offset_affected_by_page_scale(false),
       is_inner_viewport_scroll_layer(false),
       is_outer_viewport_scroll_layer(false),
@@ -35,8 +34,7 @@ bool ScrollNode::operator==(const ScrollNode& other) const {
          owning_layer_id == other.owning_layer_id &&
          scrollable == other.scrollable &&
          main_thread_scrolling_reasons == other.main_thread_scrolling_reasons &&
-         contains_non_fast_scrollable_region ==
-             other.contains_non_fast_scrollable_region &&
+         non_fast_scrollable_region == other.non_fast_scrollable_region &&

[wkorman, 2017/02/27 23:59:24]

And the SkRegion operator== logic is more complex than a bool:

https://cs.chromium.org/chromium/src/third_party/skia/src/core/SkRegion.cpp?t...

Again I think it's ok but worth commenting while reading.

          scroll_clip_layer_bounds == other.scroll_clip_layer_bounds &&
          bounds == other.bounds &&
          max_scroll_offset_affected_by_page_scale ==