Revert of Move CPU feature detection to its own file.

gyp/core.gyp

Index: gyp/core.gyp
diff --git a/gyp/core.gyp b/gyp/core.gyp
index b0cbbf9bb052d52d55fd66cf46d5930d33e12e6c..13b8217fb184d9f826a37136ed518f5b9a249538 100644
--- a/gyp/core.gyp
+++ b/gyp/core.gyp
@@ -87,6 +87,13 @@
             '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',