Remove GrSurfaceDesc member from GrSurface.

Change-Id: I0fe979994e1e3fc457b952dfb5e0090c45fad771
Reviewed-on: https://skia-review.googlesource.com/17273
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/gl/GrGLRenderTarget.cpp b/src/gpu/gl/GrGLRenderTarget.cpp
index 7d45ceb..00a7840 100644
--- a/src/gpu/gl/GrGLRenderTarget.cpp
+++ b/src/gpu/gl/GrGLRenderTarget.cpp
@@ -215,7 +215,7 @@
     if (fTexFBOID == kUnresolvableFBOID || fTexFBOID != fRTFBOID) {
         // If the render target's FBO is external (fTexFBOID == kUnresolvableFBOID), or if we own
         // the render target's FBO (fTexFBOID == fRTFBOID) then we use the provided sample count.
-        return SkTMax(1, fDesc.fSampleCnt);
+        return SkTMax(1, this->numStencilSamples());
     }
 
     // When fTexFBOID == fRTFBOID, we either are not using MSAA, or MSAA is auto resolving, so use