Disable assembly optimizations in MemorySanitizer builds of libjpeg_turbo.

BUG=chromium:178409
NOTRY=true

Review URL: https://codereview.chromium.org/170323002

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libjpeg_turbo@251747 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/libjpeg.gyp b/libjpeg.gyp
index 03dc537..8f4d193 100644
--- a/libjpeg.gyp
+++ b/libjpeg.gyp
@@ -136,7 +136,7 @@
             'simd/jsimdcpu.asm',
           ],
         }],
-        [ 'target_arch=="x64"', {
+        [ 'target_arch=="x64" and msan!=1', {
           'sources': [
             'simd/jsimd_x86_64.c',
             'simd/jccolss2-64.asm',
@@ -156,6 +156,13 @@
             'simd/jiss2red-64.asm',
           ],
         }],
+        # MemorySanitizer doesn't support assembly code, so keep it disabled in
+        # MSan builds for now.
+        [ 'msan==1', {
+          'sources': [
+            'jsimd_none.c',
+          ],
+        }],
         # The ARM SIMD implementation can be used for devices that support
         # the NEON instruction set. This can safely be done dynamically by
         # probing CPU features at runtime, if you wish.