[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/SkGr.cpp b/src/gpu/SkGr.cpp
index bbb55c8..6fe8292 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -207,11 +207,7 @@
         case SkBitmap::kARGB_4444_Config:
             return kRGBA_4444_GrPixelConfig;
         case SkBitmap::kARGB_8888_Config:
-            if (isOpaque) {
-                return kRGBX_8888_GrPixelConfig;
-            } else {
-                return kRGBA_8888_GrPixelConfig;
-            }
+            return kSkia8888_PM_GrPixelConfig;
         default:
             return kUnknown_GrPixelConfig;
     }