separate state for msaa renderability

R=robertphillips@google.com, brian@thesalomons.net

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/26695005

git-svn-id: http://skia.googlecode.com/svn/trunk@11770 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkBitmapAlphaThresholdShader.cpp b/src/effects/SkBitmapAlphaThresholdShader.cpp
index 69e22c9..6f1c94a 100644
--- a/src/effects/SkBitmapAlphaThresholdShader.cpp
+++ b/src/effects/SkBitmapAlphaThresholdShader.cpp
@@ -218,7 +218,7 @@
     }
 
     GrTextureDesc maskDesc;
-    if (context->isConfigRenderable(kAlpha_8_GrPixelConfig)) {
+    if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
         maskDesc.fConfig = kAlpha_8_GrPixelConfig;
     } else {
         maskDesc.fConfig = kRGBA_8888_GrPixelConfig;