Add copyright headers to remaining gyp files.

gyp/bench.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.
 # GYP file to build performance testbench.
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
     {
       'target_name': 'nanobench',
       'type': 'executable',
@@ skipping 21 matching lines @@
       'conditions': [
         ['skia_android_framework', {
           'libraries': [
             '-lskia',
           ],
         }],
       ],
     },
   ],
 }