Revert of Move CPU feature detection to its own file.

gyp/core.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.
 # Core Skia library code.
 {
   'targets': [
     {
       'target_name': 'core',
       'product_name': 'skia_core',
@@ skipping 69 matching lines @@
         [ 'skia_os == "win"', {
           'include_dirs': [
             'config/win',
           ],
         }],
         [ 'skia_os == "android"', {
           'dependencies': [
             'android_deps.gyp:cpu_features',
           ],
         }],
+        [ 'skia_arch_type == "arm"', {
+          # The code in SkUtilsArm.cpp can be used on an ARM-based Linux system, not only Android.
+          'sources': [
+            '../src/core/SkUtilsArm.cpp',
+            '../src/core/SkUtilsArm.h',
+          ],
+        }],
         ['skia_gpu == 1', {
           'include_dirs': [
               '../include/gpu',
               '../src/gpu',
           ],
         }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/c',
@@ skipping 15 matching lines @@
           [ 'skia_os == "win"', {
             'include_dirs': [
               'config/win',
             ],
           }],
         ],
       },
     },
   ],
 }