linux_aura: Compile ash into chrome.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 3e18a4b188df2a391f2119b76a167bb19f0da2d3..1fac2b6f96d0103d918c9bbec368fb965943b174 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -87,7 +87,7 @@
 
           'conditions': [
             # ChromeOS and Windows use Aura and Ash.
-            ['chromeos==1 or OS=="win"', {
+            ['chromeos==1 or OS=="win" or OS=="linux"', {
               'use_ash%': 1,
               'use_aura%': 1,
             }],
@@ -97,14 +97,6 @@
               '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,