Force use_ash to 0 if use_aura is 0.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index f9d2ca0ad8be559af01149becf8be2db7a505f89..98e17766f3c62e2e6cf383b2fc0346e4d0b0beab 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -75,16 +75,6 @@
               'use_aura%': 1,
             }],
 
-            # For now, Windows builds that |use_aura| should also imply using
-            # ash. This rule should be removed for the future when Windows is
-            # using the aura windows without the ash interface.
-            ['use_aura==1 and OS=="win"', {
-              'use_ash%': 1,
-            }],
-            ['use_ash==1', {
-              '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,
@@ -137,6 +127,11 @@
         'arm_version%': 7,
 
         'conditions': [
+          # Ash needs Aura.

[gab, 2013/10/04 17:54:15]

So it actually looks like the first block above defines "default values" which
(unless overwritten by chromium.gyp_env) are copied to this block which is then
responsible for changing variables based on conditions based on other variables.

(and there seems to be more nested blocks of variables below... this is crazy...
but I think this works...!)

Having this code above would not work as use_aura is always 0 if not specified
(until it is defined by the default in the previous block which is only readable
here... gyp isn't sequential line-by-line, but rather block by block... it
appears...!

[scottmg, 2013/10/04 18:20:31]

Yeah, that's what I was trying to say before. Crazy indeed. lgtm2.

+          ['use_aura==0', {
+            'use_ash%': 0,
+          }],
+
           # Set default value of toolkit_views based on OS.
           ['OS=="win" or chromeos==1 or use_aura==1', {
             'toolkit_views%': 1,