Add support for animations in vector icons.

ui/gfx/vector_icon_types.h

Index: ui/gfx/vector_icon_types.h
diff --git a/ui/gfx/vector_icon_types.h b/ui/gfx/vector_icon_types.h
index b18000b41fe304b8ade4ae9bdde408243741b068..26545275718a3eaad9bb08df5535e992ac84ef40 100644
--- a/ui/gfx/vector_icon_types.h
+++ b/ui/gfx/vector_icon_types.h
@@ -58,6 +58,10 @@ enum CommandType {
   // Flips the x-axis in RTL locales. Default is false, this command sets it to
   // true.
   FLIPS_IN_RTL,
+  // Defines a timed transition for other elements.
+  TRANSITION_FROM,
+  TRANSITION_TO,
+  TRANSITION_END,

[sadrul, 2017/05/09 22:12:03]

Can you please document the parameters here?

[Evan Stade, 2017/05/09 22:45:14]

once the dust settles, I plan to update the docs on the chromium dev site for
vector icons, and possible create a README.md. But I can add a short note here
about the params as well.

   // Marks the end of the list of commands.
   END
 };