Add SkNativeGLContext implementation for iOS.

R=caryclark@google.com
Review URL: https://codereview.appspot.com/6589055

git-svn-id: http://skia.googlecode.com/svn/trunk@5767 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/gpu.gyp b/gyp/gpu.gyp
index 94988ad..98ab257 100644
--- a/gyp/gpu.gyp
+++ b/gyp/gpu.gyp
@@ -6,7 +6,7 @@
         ],
       }],
       ['skia_os != "mac"', {
-        'sources/': [ ['exclude', '_mac.(h|cpp)$'],
+        'sources/': [ ['exclude', '_mac.(h|cpp|m|mm)$'],
         ],
       }],
       ['skia_os != "linux"', {
@@ -14,7 +14,7 @@
         ],
       }],
       ['skia_os != "ios"', {
-        'sources/': [ ['exclude', '_iOS.(h|cpp)$'],
+        'sources/': [ ['exclude', '_iOS.(h|cpp|m|mm)$'],
         ],
       }],
       ['skia_os != "android"', {