Touchpad scroll latching enabled for Mac behind flag.

cc/input/scroll_state_data.h

Index: cc/input/scroll_state_data.h
diff --git a/cc/input/scroll_state_data.h b/cc/input/scroll_state_data.h
index 90339649f5ffbd475d17f5b36421923e1cae812e..314bacf9a52f5f7325824d7b713db3bdd77c5cfc 100644
--- a/cc/input/scroll_state_data.h
+++ b/cc/input/scroll_state_data.h
@@ -32,6 +32,9 @@ class CC_EXPORT ScrollStateData {
   bool is_beginning;
   bool is_in_inertial_phase;
   bool is_ending;
+  // True if the next event may be the start of a fling (is_beginning &&
+  // in_inertial_phase). May only be true if is_ending == true.
+  bool may_precede_fling;

[tdresser, 2016/11/14 16:02:29]

It might be worth using a three valued enum instead of two bools here, to avoid
the risk of invalid state, and to make it clearer that you can't have
"may_precede_fling" and "!is_ending".

[sahel, 2016/11/18 16:13:58]

is_ending now is handled very similarly to is_beginning (there is kind of a
symmetry.) and, it's accessed in more than 10 different files. I'll change it if
you still prefer to have the 3 valued enum.

[tdresser, 2016/11/22 21:44:40]

Acknowledged.

 
   bool should_propagate;
   bool from_user_input;