[GPU] Add explicit byte order and PM vs. UPM 8888 configs

Review URL: http://codereview.appspot.com/5347042/



git-svn-id: http://skia.googlecode.com/svn/trunk@2618 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAtlas.cpp b/src/gpu/GrAtlas.cpp
index 0838895..244f694 100644
--- a/src/gpu/GrAtlas.cpp
+++ b/src/gpu/GrAtlas.cpp
@@ -141,7 +141,7 @@
         case kA565_GrMaskFormat:
             return kRGB_565_GrPixelConfig;
         case kA888_GrMaskFormat:
-            return kRGBA_8888_GrPixelConfig;
+            return kSkia8888_PM_GrPixelConfig;
         default:
             GrAssert(!"unknown maskformat");
     }