Fix accessibility issues on most visited page for android's NTP.

Fix accessibility issues on most visited page for android's NTP.

Do not modify the DOM of the most visited page if nothing has changed, which
is often the case as the top sites are polled periodically just to make sure
they are up to date.

Also, moves the event listener to a node with a text attribute that allows it
to be selected in accessibility mode.

Makes some markup nodes as skippable in accessibility mode by marking them as
having empty alt text.

BUG=155450
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=162246

[Evan Stade, 2012-10-16 03:00:08]

I assume you added me as an OWNER of resources. Instead please add an OWNERS
file to ntp_android/

[aruslan, 2012-10-16 18:24:42]

LGTM

[commit-bot: I haz the power, 2012-10-16 18:43:13]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a lowly provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Ted C, 2012-10-16 18:46:11]

@jcivelli for lgtm stamp

[Jay Civelli, 2012-10-16 18:55:50]

lgtm

[commit-bot: I haz the power, 2012-10-16 18:58:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tedchoc@chromium.org/11155022/1

[commit-bot: I haz the power, 2012-10-16 21:08:38]

Change committed as 162246