material throbber, take 2

material throbber, take 2

Due to a misunderstanding on my part, the initial implementation represented the "waiting" state, which is used while waiting for a network response in a Chrome tab. Most throbbers should use the "normal"/"spinning" state. This ports the CSS animations in MD_spinner_blue.svg to skia commands, and uses it in the card unmasking dialog.

After some investigation, I've realized that very few places in Chrome actually use the Throbber class. Tabs, for example, draw directly onto a canvas. So the next step will be to refactor this functionality into a ThrobberPainter class so tabs can use it. The reason I am not already doing this is I want to verify with the designers that this version looks good before I work on bringing it to more of Chrome.

BUG=259556, 473342
Committed: https://crrev.com/90104a67209d6a6a9e01845335402a37303fceaf
Cr-Commit-Position: refs/heads/master@{#327105}

[Evan Stade, 2015-04-27 17:54:47]

estade@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2015-04-27 19:06:23]

LGTM

[Evan Stade, 2015-04-27 19:27:35]

The CQ bit was checked by estade@chromium.org

[commit-bot: I haz the power, 2015-04-27 19:28:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1098853005/60001

[commit-bot: I haz the power, 2015-04-27 19:49:59]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-04-27 19:51:54]

Patchset 4 (id:??) landed as
https://crrev.com/90104a67209d6a6a9e01845335402a37303fceaf
Cr-Commit-Position: refs/heads/master@{#327105}