add enable flag for SKIA_GPU, set to 0 by default (set to 1 for local testing)
add enable flag for SKIA_GPU, set to 0 by default (set to 1 for local testing)

Review URL: http://codereview.chromium.org/6461016

git-svn-id: http://src.chromium.org/svn/trunk/src@74276 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: f11a8e64233786eb895e7b39e27b1c2d95b867d3
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser