Add copyright headers to remaining gyp files.

gyp/iOSShell.gyp

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 #
 {
   'conditions' : [
     [ 'skia_os == "ios"', {
       'targets': [
         {
           'target_name': 'iOSShell',
           'type': 'executable',
           'mac_bundle' : 1,
           'includes': [
@@ skipping 72 matching lines @@
               'dependencies': [
                 'gputest.gyp:skgputest',
               ],
             }],
           ],
         },
       ],
     }],
   ]
 }