Quick bandaid for chromium:611002.

src/opts/SkBlitRow_opts.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkBlitRow_opts_DEFINED
 #define SkBlitRow_opts_DEFINED
 
@@ skipping 172 matching lines @@
         vst1_u32(dst+0, vreinterpret_u32_u8(dst0));
         vst1_u32(dst+2, vreinterpret_u32_u8(dst2));
 
         src += 4;
         dst += 4;
         len -= 4;
     }
 #endif
 
     while (len-- > 0) {
-        if (*src) {
+        // This 0xFF000000 is not semantically necessary, but for compatibility
+        // with chromium:611002 we need to keep it until we figure out where
+        // the non-premultiplied src values (like 0x00FFFFFF) are coming from.
+        // TODO(mtklein): sort this out and assert *src is premul here.
+        if (*src & 0xFF000000) {
             *dst = (*src >= 0xFF000000) ? *src : SkPMSrcOver(*src, *dst);
         }
         src++;
         dst++;
     }
 }
 
 }  // SK_OPTS_NS
 
 #endif//SkBlitRow_opts_DEFINED