Revert of Revert of Revert of Set the javac target and source to 1.7

Revert of Revert of Revert of Set the javac target and source to 1.7 (patchset #1 id:1 of https://codereview.chromium.org/601983002/)

Reason for revert:
Broke Android bots:
http://build.chromium.org/p/chromium.linux/builders/Android%20Arm64%20Builder%20%28dbg%29/builds/2225
http://build.chromium.org/p/chromium.linux/builders/Android%20Builder%20%28dbg%29/builds/66337

Original issue's description:
> Revert of Revert of Set the javac target and source to 1.7 (patchset #1 id:1 of https://chromiumcodereview.appspot.com/579543003/)
>
> Reason for revert:
> All the bots have been switched to Java 7 according to https://code.google.com/p/chromium/issues/detail?id=411503#c19
>
> Original issue's description:
> > Revert of Set the javac target and source to 1.7 (patchset #2 id:20001 of https://chromiumcodereview.appspot.com/545363002/)
> >
> > Reason for revert:
> > Not all bots have Java 7 yet :(
> >
> > Original issue's description:
> > > Set the javac target and source to 1.7
> > >
> > > BUG=336589
> > > TBR=yfriedman@chromium.org
> > >
> > > Committed: https://crrev.com/165c0f17fe5760a3f346940d4fb2574d62cfe53b
> > > Cr-Commit-Position: refs/heads/master@{#295162}
> >
> > TBR=cjhopman@chromium.org,yfriedman@chromium.org
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=336589
> >
> > Committed: https://crrev.com/094138696e943744d1489ebb98276b116eafed99
> > Cr-Commit-Position: refs/heads/master@{#295165}
>
> TBR=cjhopman@chromium.org,yfriedman@chromium.org
> BUG=336589
>
> Committed: https://crrev.com/119c6fa8247481d2e36910d30175d0214fd2ece5
> Cr-Commit-Position: refs/heads/master@{#296630}

TBR=cjhopman@chromium.org,yfriedman@chromium.org,aurimas@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=336589
Committed: https://crrev.com/8be2c3f7a14b6191a5a38f187346ce4a36997a6e
Cr-Commit-Position: refs/heads/master@{#296632}

[Lei Zhang, 2014-09-25 03:08:23]

Created Revert of Revert of Revert of Set the javac target and source to 1.7

[commit-bot: I haz the power, 2014-09-25 03:08:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/603833002/1

[commit-bot: I haz the power, 2014-09-25 03:09:27]

Committed patchset #1 (id:1) as 453000a30a8856a41bca4dc249f6ab1a7a8a1b6b

[commit-bot: I haz the power, 2014-09-25 03:10:10]

Patchset 1 (id:??) landed as
https://crrev.com/8be2c3f7a14b6191a5a38f187346ce4a36997a6e
Cr-Commit-Position: refs/heads/master@{#296632}

[Lei Zhang, 2014-09-25 03:22:03]

Another red bot:
http://build.chromium.org/p/chromium.linux/builders/Android%20Builder/builds/...

[aurimas (slooooooooow), 2014-09-25 21:14:23]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/599633006/ by aurimas@chromium.org.

The reason for reverting is: *Fingers crossed* all the Android builders are on
Java 7 now.
Please comment on
https://code.google.com/p/chromium/issues/detail?id=411503#c31 if you see any
Android builders failing to compile due to unknown target version 1.7..