Disable linux_aura on the main builders.

Currently, browser_tests are running 2x-3x slower on the bots. Our first
dev channel has been very enlightening and got people to file all sorts
of helpful bugs.

BUG=319075,125106,303342,318961
NOTRY=True
R=cmp@chromium.org

Review URL: https://codereview.chromium.org/73323002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@235280 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -84,14 +84,6 @@
               'use_aura%': 1,
             }],
 
-            # ToT Linux should be aura.
-            #
-            # TODO(erg): Merge this into the previous block once compiling with
-            # aura safely implies including ash capabilities.
-            ['OS=="linux"', {
-              'use_aura%': 1,
-            }],
-
             # Whether we're a traditional desktop unix.
             ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") and chromeos==0', {
               'desktop_linux%': 1,