separate state for msaa renderability

src/gpu/GrGpu.cpp

Index: src/gpu/GrGpu.cpp
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index 186091f20cc176152ea7570ec2c3efb32fc18011..4c3e5de543a6227671f4bd64a5ab2c7ebda0a8bd 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -113,6 +113,10 @@ GrTexture* GrGpu::createTexture(const GrTextureDesc& desc,
     if (kUnknown_GrPixelConfig == desc.fConfig) {
         return NULL;
     }
+    if ((desc.fFlags & kRenderTarget_GrTextureFlagBit) &&
+        !this->caps()->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
+        return NULL;
+    }
 
     this->handleDirtyContext();
     GrTexture* tex = this->onCreateTexture(desc, srcData, rowBytes);