Revert of Revert of Revert of Revert of Set the javac target and source to 1.7 (patch...

Revert of Revert of Revert of Revert of Set the javac target and source to 1.7 (patchset #1 id:1 of https://codereview.chromium.org/603833002/)

Reason for revert:
*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.

Original issue's description:
> 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}

TBR=cjhopman@chromium.org,yfriedman@chromium.org,thestig@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=336589

Review URL: https://codereview.chromium.org/599633006

Cr-Commit-Position: refs/heads/master@{#296794}