Add SSE4 optimization of S32A_Opaque_Blitrow

src/opts/SkBlitRow_opts_SSE4.h

Index: src/opts/SkBlitRow_opts_SSE4.h
diff --git a/src/opts/SkBlitRow_opts_SSE4.h b/src/opts/SkBlitRow_opts_SSE4.h
new file mode 100644
index 0000000000000000000000000000000000000000..6c6276eae0efa46cec4f80ed13f6876f817d18a5
--- /dev/null
+++ b/src/opts/SkBlitRow_opts_SSE4.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2014 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBlitRow_opts_SSE4_DEFINED
+#define SkBlitRow_opts_SSE4_DEFINED
+
+#include "SkBlitRow.h"
+
+/* Check if we are able to build assembly code, GCC/AT&T syntax.
+ * Had problems with LLVM-GCC 4.2.
+ */
+#if defined(__clang__) || (defined(__GNUC__) && !defined(SK_BUILD_FOR_MAC))
+extern "C" void S32A_Opaque_BlitRow32_SSE4_asm(SkPMColor* SK_RESTRICT dst,
+                                               const SkPMColor* SK_RESTRICT src,
+                                               int count, U8CPU alpha);
+
+#define SK_ATT_ASM_SUPPORTED
+#endif
+
+#endif
+