Revert 132760 - Metro/HiDPI: Move 1x icons into separate pak file

Revert 132760 - Metro/HiDPI: Move 1x icons into separate pak file

Currently all 1x art files are repacked into chrome.pak files.

This is a problem on Windows where we want to choose which pak file to load based on metro and DPI scale.

As a first step this CL does the following:
 - add a new enable_hidpi build flag. This allows us to test HiDPI mode on Windows Chrome.
 - stop packing theme_resources_standard.pak and ui_resources_standard.pak into chrome.pak
 - update the Mac and Windows installer code to package the extra pak files.

Note, I'll be updating the Linux installer script in a separate CL. I'm still looking into the ChromeOS situation.

BUG=114311
TEST=Ran on Windows, and Mac and Linux.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=132517

Review URL: http://codereview.chromium.org/10024050

TBR=sail@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=132804