scope ComputeIsOpaque with SkBitmap

BUG=

Review URL: https://codereview.chromium.org/32653002

git-svn-id: http://skia.googlecode.com/svn/trunk@11879 2bbb7eff-a529-9590-31e7-b0007b416f81

src/ports/SkImageDecoder_WIC.cpp

@@ -240,7 +240,7 @@ bool SkImageDecoder_WIC::decodeStream(SkStream* stream, SkBitmap* bm, WICModes w
         );
 
         // Note: we don't need to premultiply here since we specified PBGRA
-        if (ComputeIsOpaque(*bm)) {
+        if (SkBitmap::ComputeIsOpaque(*bm)) {
             bm->setAlphaType(kOpaque_SkAlphaType);
         }
     }