input[type=search]: Flip the position of cancel button in RTL.
We didn't do it because Safari didn't. Safari recently changed the behavior.
This CL removes a UA style to force LTR, and update some tests and WebUI style.
BUG=
67848
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
Committed:
https://crrev.com/7017637cecdd300f3a90f6afbde474ea4a98a418
Cr-Commit-Position: refs/heads/master@{#410495}