mac: Basic HighDPI implementation for web contents.

Depends on https://bugs.webkit.org/show_bug.cgi?id=88596

The basics work, but a lot of stuff is broken (e.g. switching
resolutions while chrome is running).

BUG=31960
TEST=Go HighDPI, launch chrome. No longer pixely.
TBR=sky

Review URL: https://chromiumcodereview.appspot.com/10537067

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@141211 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed