Ash: Fix hit testing for the bottom pixels of tabs

Ash: Fix hit testing for the bottom pixels of tabs

* Ash uses a taller content area shadow, so the toolbar needs to avoid taking mouse clicks along its top 2 pixels, as they overlap the tab strip.
* Added more GetClassName() implementations for views to help with future debugging.
* Removed an attempt to forward-declare an enum.

BUG=123354
TEST=manual, ensure that hovering mouse along the very bottom of a tab results in the hover-glow effect

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=132415

[James Cook, 2012-04-13 23:05:23]

Scott, PTAL.

[sky, 2012-04-13 23:30:10]

LGTM

[commit-bot: I haz the power, 2012-04-14 00:20:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jamescook@chromium.org/10082029/1

[commit-bot: I haz the power, 2012-04-14 03:28:08]

Try job failure for 10082029-1 (retry) on mac_rel for step "browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_rel&nu...