Simplify xcode_settings block in common.gypi a bit.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index cbea95780ec9259301466486890457d51b26eb90..1351edcfaf7ca8f2eda06126aec181c9ba133ca5 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -6373,6 +6373,7 @@
       # configured SDK to show properly in the Xcode UI, SDKROOT must be set
       # here at the project level.
       ['OS=="mac"', {
+        'ARCHS': [ 'x86_64' ],
         'conditions': [
           ['mac_sdk_path==""', {
             'SDKROOT': 'macosx<(mac_sdk)',  # -isysroot
@@ -6382,6 +6383,8 @@
         ],
       }],
       ['OS=="ios"', {
+        # Target both iPhone and iPad.
+        'TARGETED_DEVICE_FAMILY': '1,2',
         'conditions': [
           ['ios_sdk_path==""', {
             'conditions': [
@@ -6397,23 +6400,6 @@
           }],
         ],
       }],
-      ['OS=="ios"', {
-        # Target both iPhone and iPad.
-        'TARGETED_DEVICE_FAMILY': '1,2',
-      }, {  # OS!="ios"
-        'conditions': [
-          ['target_arch=="x64"', {
-            'ARCHS': [
-              'x86_64'
-            ],
-          }],
-          ['target_arch=="ia32"', {
-            'ARCHS': [
-              'i386'

[Mark Mentovai, 2016/01/04 16:15:49]

Double-check with someone from remoting that they’re not still building their
pref pane as 32-bit (or fat).

[Nico, 2016/01/04 16:29:54]

Would that be a problem? They used to locally set ARCHS in their target (lhs of
https://codereview.chromium.org/1547533002/diff/160001/remoting/remoting_host...
-- they currently don't set ARCHS but that change looks wrong to me)

-            ],
-          }],
-        ],
-      }],
     ],
 
     # The Xcode generator will look for an xcode_settings section at the root