Revert of Removing X11 native_event uses for key events.

Revert of Removing X11 native_event uses for key events. (patchset #6 id:160001 of https://codereview.chromium.org/479873002/)

Reason for revert:
Causing check_licenses to fail on android_clang_dbg_recipe trybot:
The following files are whitelisted unnecessarily. You must remove the following files from the whitelist.
content/browser/renderer_host/web_input_event_aurax11.cc
The following files are whitelisted, but do not exist.
content/browser/renderer_host/web_input_event_aurax11.cc

Original issue's description:
> Removing uses of X11 native key events.
> 
> BUG=380349
> 
> Committed: https://chromium.googlesource.com/chromium/src/+/bbb7ea7c66f18298079eea4a6b24834986f4a822

TBR=sadrul@chromium.org,sky@chromium.org,erg@chromium.org,jamesr@chromium.org,kpschoedel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=380349
Committed: https://crrev.com/97b7fc9ff9b9eade1654f1394b5992c2c2a17ef9
Cr-Commit-Position: refs/heads/master@{#293254}

[dcheng, 2014-09-04 03:50:18]

Created Revert of Removing X11 native_event uses for key events.

[commit-bot: I haz the power, 2014-09-04 03:50:46]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dcheng@chromium.org/536313002/1

[commit-bot: I haz the power, 2014-09-04 03:53:09]

Committed patchset #1 (id:1) as 5e96641ef9b0d92a2475c82f4b2f7067e0d7175b

[dcheng, 2014-09-04 03:53:37]

One of many failures can be seen at
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_clang_d...

[commit-bot: I haz the power, 2014-09-10 03:29:37]

Patchset 1 (id:??) landed as
https://crrev.com/97b7fc9ff9b9eade1654f1394b5992c2c2a17ef9
Cr-Commit-Position: refs/heads/master@{#293254}