Implement progress bar spec (determinate and indeterminate).

ui/gfx/animation/linear_animation.h

Index: ui/gfx/animation/linear_animation.h
diff --git a/ui/gfx/animation/linear_animation.h b/ui/gfx/animation/linear_animation.h
index d9e6de32374afcf862285c9b92e953d04b870eb8..fa74c82be3082a56c113cc339914f1d9a6ee315d 100644
--- a/ui/gfx/animation/linear_animation.h
+++ b/ui/gfx/animation/linear_animation.h
@@ -24,6 +24,8 @@ class GFX_EXPORT LinearAnimation : public Animation {
   // duration can change between calls to Start() and we need to
   // expose this interface.
   LinearAnimation(int frame_rate, AnimationDelegate* delegate);
+  // As above, but uses a default frame rate.
+  explicit LinearAnimation(AnimationDelegate* delegate);

[sky, 2016/09/13 02:30:08]

How about the following as the only constructor:

explicit LinearAnimation(AnimationDelegate* delegate,
frame_default = kDefaultFrameFrame);
?

[Evan Stade, 2016/09/13 15:45:39]

Done.

 
   // Initializes all fields.
   LinearAnimation(int duration, int frame_rate, AnimationDelegate* delegate);