Disable assembly optimizations in MemorySanitizer builds.

BUG=chromium:344505, chromium:373739
R=kjellander@google.com, mflodman@chromium.org

Review URL: https://webrtc-codereview.appspot.com/14849004

Patch from Sergey Matveev <earthdok@chromium.org>.

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1028 16f28f9a-4ce2-e073-06de-1de4eb20be90

BUILD.gn

@@ -77,6 +77,12 @@ source_set("libyuv") {
     defines += [ "HAVE_JPEG" ]
   }
 
+  if (is_msan) {
+    # MemorySanitizer does not support assembly code yet.
+    # http://crbug.com/344505
+    defines += [ "LIBYUV_DISABLE_X86" ]
+  }
+
   deps = [
     "//third_party:jpeg",
   ]

libyuv.gyp

@@ -104,6 +104,13 @@
             'LIBYUV_NEON',
           ]
         }],
+        # MemorySanitizer does not support assembly code yet.
+        # http://crbug.com/344505
+        [ 'msan == 1', {
+          'defines': [
+            'LIBYUV_DISABLE_X86',
+          ],
+        }],
       ],
       'defines': [
         # Enable the following 3 macros to turn off assembly for specified CPU.