Experiment with AVX optimizations for FMAC, FMUL operations.

media/BUILD.gn

Index: media/BUILD.gn
diff --git a/media/BUILD.gn b/media/BUILD.gn
index 2d62c02ba673b121071d541e8281c47b0e852ead..8a6390bbfd80b8b320e14887986e23aaf9330675 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -848,11 +848,26 @@ component("shared_memory_support") {
     ":media_implementation",
   ]
   deps = [
+    ":media_avx",
     "//base",
     "//ui/gfx/geometry",
   ]
 }
 
+if (current_cpu == "x86" || current_cpu == "x64") {
+  source_set("media_avx") {
+    configs += [ "//media:media_implementation" ]
+    sources = [
+      "base/vector_math_avx.cc",
+    ]
+    if (is_win) {
+      cflags = [ "/arch:AVX" ]
+    } else {
+      cflags = [ "-mavx" ]
+    }
+  }
+}
+
 # TODO(watk): Refactor tests that could be made to run on Android. See
 # http://crbug.com/570762
 if (media_use_ffmpeg && !is_android) {