Remove duplicate CPU detection code; use base::CPU instead.

media/media.gyp

Index: media/media.gyp
diff --git a/media/media.gyp b/media/media.gyp
index 2a8c6c6aeb406f6311413654c5399cedff34b408..056407f5a912e35cd8dfc64377e5bf9179b56f66 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -445,36 +445,11 @@
       ],
     },
     {
-      'target_name': 'cpu_features',
-      'type': 'static_library',
-      'include_dirs': [
-        '..',
-      ],
-      'conditions': [
-        [ 'target_arch == "ia32" or target_arch == "x64"', {
-          'sources': [
-            'base/cpu_features_x86.cc',
-          ],
-        }],
-        [ 'target_arch == "arm"', {
-          'sources': [
-            'base/cpu_features_arm.cc',
-          ],
-        }],
-      ],
-      'sources': [
-        'base/cpu_features.h',
-      ],
-    },
-    {
       'target_name': 'yuv_convert',
       'type': 'static_library',
       'include_dirs': [
         '..',
       ],
-      'dependencies': [
-        'cpu_features',
-      ],
       'conditions': [
         ['order_profiling != 0', {
           'target_conditions' : [