Add product mode:

runtime/tools/gyp/runtime-configurations.gypi

Index: runtime/tools/gyp/runtime-configurations.gypi
diff --git a/runtime/tools/gyp/runtime-configurations.gypi b/runtime/tools/gyp/runtime-configurations.gypi
index 0b053c4b6248ea73a0426485f3a3fe895a4daffb..e5fc998ee79e0462471e2e5b9e2d39e72dfc1438 100644
--- a/runtime/tools/gyp/runtime-configurations.gypi
+++ b/runtime/tools/gyp/runtime-configurations.gypi
@@ -31,22 +31,6 @@
         },
       },
 
-      'Dart_Debug': {
-        'abstract': 1,
-        'defines': [
-          'DEBUG',
-        ],
-        'xcode_settings': {
-          'GCC_OPTIMIZATION_LEVEL': '<(dart_debug_optimization_level)',
-        },
-      },
-
-      'Debug': {
-        'defines': [
-          'DEBUG',
-        ],
-      },
-
       'Dart_ia32_Base': {
         'abstract': 1,
         'xcode_settings': {
@@ -113,12 +97,35 @@
         },
       },
 
+      'Dart_Debug': {
+        'abstract': 1,
+        'defines': [
+          'DEBUG',
+        ],
+        'xcode_settings': {

[Florian Schneider, 2016/02/03 18:00:21]

Why is xcode_settings not in configurations_xcode.gypi? I think it works either
way, but seems a bit strange.

+          'GCC_OPTIMIZATION_LEVEL': '<(dart_debug_optimization_level)',
+        },
+      },
+
+      'Debug': {
+        'defines': [
+          'DEBUG',
+        ],
+      },
+
       'Dart_Release': {
         'abstract': 1,
         'xcode_settings': {
           'GCC_OPTIMIZATION_LEVEL': '3',
         },
       },
+
+      'Dart_Product' : {
+        'abstract': 1,
+        'xcode_settings': {
+          'GCC_OPTIMIZATION_LEVEL': '3',
+        }
+      },
     },
   },
 }