Revert of Cleanup: Remove unneeded SSE2 checks and unused code. (patchset #4 of https://codereview.chromium.org/459603003/)

Reason for revert:
Passed the win x64 trybot, but failed on the win 64 builder.

Original issue's description:
> Cleanup: Remove unneeded SSE2 checks and unused code.
>
> BUG=349320
>
> Committed: https://chromium.googlesource.com/chromium/src/+/b2cd99b39c3744f61231f8818f6c7a3d2881f0f0

TBR=cpu@chromium.org,dalecurtis@chromium.org,senorblanco@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=349320

Review URL: https://codereview.chromium.org/513663002

Cr-Commit-Position: refs/heads/master@{#292101}

1 files changed, 26 insertions, 17 deletions

diff --git a/media/base/yuv_convert.cc b/media/base/yuv_convert.cc
index 4c53067..5ad8f30 100644
--- a/media/base/yuv_convert.cc
+++ b/media/base/yuv_convert.cc
@@ -165,33 +165,42 @@ void InitializeCPUSpecificYUVConversions() {
   // Assembly code confuses MemorySanitizer.
 #if defined(ARCH_CPU_X86_FAMILY) && !defined(MEMORY_SANITIZER)
   base::CPU cpu;
-
-  g_convert_yuva_to_argb_proc_ = ConvertYUVAToARGB_MMX;
+  if (cpu.has_mmx()) {
+    g_convert_yuv_to_rgb32_row_proc_ = ConvertYUVToRGB32Row_MMX;
+    g_scale_yuv_to_rgb32_row_proc_ = ScaleYUVToRGB32Row_MMX;
+    g_convert_yuv_to_rgb32_proc_ = ConvertYUVToRGB32_MMX;
+    g_convert_yuva_to_argb_proc_ = ConvertYUVAToARGB_MMX;
+    g_linear_scale_yuv_to_rgb32_row_proc_ = LinearScaleYUVToRGB32Row_MMX;
 
 #if defined(MEDIA_MMX_INTRINSICS_AVAILABLE)
-  g_filter_yuv_rows_proc_ = FilterYUVRows_MMX;
-  g_empty_register_state_proc_ = EmptyRegisterStateIntrinsic;
+    g_filter_yuv_rows_proc_ = FilterYUVRows_MMX;
+    g_empty_register_state_proc_ = EmptyRegisterStateIntrinsic;
 #else
-  g_empty_register_state_proc_ = EmptyRegisterState_MMX;
+    g_empty_register_state_proc_ = EmptyRegisterState_MMX;
 #endif
+  }
 
-  g_convert_yuv_to_rgb32_row_proc_ = ConvertYUVToRGB32Row_SSE;
-  g_scale_yuv_to_rgb32_row_proc_ = ScaleYUVToRGB32Row_SSE;
-  g_linear_scale_yuv_to_rgb32_row_proc_ = LinearScaleYUVToRGB32Row_SSE;
-  g_convert_yuv_to_rgb32_proc_ = ConvertYUVToRGB32_SSE;
+  if (cpu.has_sse()) {
+    g_convert_yuv_to_rgb32_row_proc_ = ConvertYUVToRGB32Row_SSE;
+    g_scale_yuv_to_rgb32_row_proc_ = ScaleYUVToRGB32Row_SSE;
+    g_linear_scale_yuv_to_rgb32_row_proc_ = LinearScaleYUVToRGB32Row_SSE;
+    g_convert_yuv_to_rgb32_proc_ = ConvertYUVToRGB32_SSE;
+  }
 
-  g_filter_yuv_rows_proc_ = FilterYUVRows_SSE2;
-  g_convert_rgb32_to_yuv_proc_ = ConvertRGB32ToYUV_SSE2;
+  if (cpu.has_sse2()) {
+    g_filter_yuv_rows_proc_ = FilterYUVRows_SSE2;
+    g_convert_rgb32_to_yuv_proc_ = ConvertRGB32ToYUV_SSE2;
 
 #if defined(ARCH_CPU_X86_64)
-  g_scale_yuv_to_rgb32_row_proc_ = ScaleYUVToRGB32Row_SSE2_X64;
+    g_scale_yuv_to_rgb32_row_proc_ = ScaleYUVToRGB32Row_SSE2_X64;
 
-  // Technically this should be in the MMX section, but MSVC will optimize out
-  // the export of LinearScaleYUVToRGB32Row_MMX, which is required by the unit
-  // tests, if that decision can be made at compile time.  Since all X64 CPUs
-  // have SSE2, we can hack around this by making the selection here.
-  g_linear_scale_yuv_to_rgb32_row_proc_ = LinearScaleYUVToRGB32Row_MMX_X64;
+    // Technically this should be in the MMX section, but MSVC will optimize out
+    // the export of LinearScaleYUVToRGB32Row_MMX, which is required by the unit
+    // tests, if that decision can be made at compile time.  Since all X64 CPUs
+    // have SSE2, we can hack around this by making the selection here.
+    g_linear_scale_yuv_to_rgb32_row_proc_ = LinearScaleYUVToRGB32Row_MMX_X64;
 #endif
+  }
 
   if (cpu.has_ssse3()) {
     g_convert_rgb24_to_yuv_proc_ = &ConvertRGB24ToYUV_SSSE3;