Fixes couple of bugs in the TabStrip that could cause tabs to dance

Fixes couple of bugs in the TabStrip that could cause tabs to dance
around. Both only occurred when the active tab width differs from
inactive tab width (lots-o-tabs).
. ResizeLayoutTabs() had an optimization that avoided doing anything
  if the width of the first tab hasn't changed. Problems is if the
  first tab is active and inactive tabs have a smaller width than
  active tabs than the width won't have changed but we still need to
  layout. I removed the optimization.
. If selecting a tab triggers a bounds change the coordinates used by
  tab dragging would be wrong (because they extract them from the
  event, which is in the original coordinates).
. Needed to tweak rtl code.

BUG=140747
TEST=see bug, but make sure no weird behavior with tab selection/dragging on
windows/chrome-os.
R=ben@chromium.org


Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=175991

[Ben Goodger (Google), 2013-01-09 23:44:06]

lgtm

[commit-bot: I haz the power, 2013-01-10 00:01:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sky@chromium.org/11821036/1

[commit-bot: I haz the power, 2013-01-10 02:21:06]

Change committed as 175991