Relanding 7914



git-svn-id: http://skia.googlecode.com/svn/trunk@7940 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrClipMaskManager.cpp b/src/gpu/GrClipMaskManager.cpp
index 3bdb332..99068c7 100644
--- a/src/gpu/GrClipMaskManager.cpp
+++ b/src/gpu/GrClipMaskManager.cpp
@@ -397,7 +397,11 @@
         desc.fFlags = kRenderTarget_GrTextureFlagBit;
         desc.fWidth = clipSpaceIBounds.width();
         desc.fHeight = clipSpaceIBounds.height();
-        desc.fConfig = kAlpha_8_GrPixelConfig;
+        desc.fConfig = kRGBA_8888_GrPixelConfig;
+        if (this->getContext()->isConfigRenderable(kAlpha_8_GrPixelConfig)) {
+            // We would always like A8 but it isn't supported on all platforms
+            desc.fConfig = kAlpha_8_GrPixelConfig;
+        }
 
         fAACache.acquireMask(clipStackGenID, desc, clipSpaceIBounds);
     }