Add webkit image resources to new scale-specific location

Add webkit image resources to new scale-specific location

This is a direct-submit to put the binary files in their new place (to enable
running try jobs, CQ, etc.).  The real work/review will happen in
http://codereview.chromium.org/10701105/, at which time I'll remove the
corresponding images from their old location.

Also adds the 2x version of textarea_resize_corner.

TBR=tony@chromium.org
BUG=134046
TEST=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=148389