Cleanup: Remove unneeded SSE2 checks and unused code.

media/base/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/ui.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//media/media_options.gni")
 
@@ skipping 357 matching lines @@
     configs += [ "//media:media_config" ]
     if (!is_win) {
       cflags = [ "-msse2" ]
     }
   }
 
   import("//third_party/yasm/yasm_assemble.gni")
   yasm_assemble("media_yasm") {
     sources = [
       "simd/convert_rgb_to_yuv_ssse3.asm",
-      "simd/convert_yuv_to_rgb_mmx.asm",
       "simd/convert_yuv_to_rgb_sse.asm",
       "simd/convert_yuva_to_argb_mmx.asm",
       "simd/empty_register_state_mmx.asm",
       "simd/linear_scale_yuv_to_rgb_mmx.asm",
       "simd/linear_scale_yuv_to_rgb_sse.asm",
       "simd/scale_yuv_to_rgb_mmx.asm",
       "simd/scale_yuv_to_rgb_sse.asm",
     ]
 
     # TODO(ajwong): Only export if shared_library build...
@@ skipping 34 matching lines @@
       if (is_posix) {
         yasm_flags += [ "-DELF" ]
         if (cpu_arch == "x64") {
         # TODO(ajwong): Why isn't this true in mac?
           yasm_flags += [ "-DPIC" ]
         }
       }
     }
   }
 }