Re-applying build/common.gypi patch from http://codereview.chromium.org/195078
Re-applying build/common.gypi patch from http://codereview.chromium.org/195078

The previous patch was reverted until buildbot master was restarted.

After the restart, GYP_DEFINES contains "release_valgrind_build=1"
http://build.chromium.org/buildbot/waterfall/builders/Chromium Linux Builder (valgrind)/builds/2/steps/gclient/logs/stdio
Review URL: http://codereview.chromium.org/196140

git-svn-id: http://src.chromium.org/svn/trunk/src@26564 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: c5f224bf00e5a550cd70a7f9bd83191b16cf38bb
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