Fix assertion about GPU memory size when the target is not FBO 0

src/gpu/gl/GrGLRenderTarget.cpp

Index: src/gpu/gl/GrGLRenderTarget.cpp
diff --git a/src/gpu/gl/GrGLRenderTarget.cpp b/src/gpu/gl/GrGLRenderTarget.cpp
index e93c5c100be2a206756e107c675acd10d4bfe072..36a7bd78fe88a1b60ad8d235fc6d7f74ad6d1d0f 100644
--- a/src/gpu/gl/GrGLRenderTarget.cpp
+++ b/src/gpu/gl/GrGLRenderTarget.cpp
@@ -40,7 +40,7 @@ void GrGLRenderTarget::init(const GrSurfaceDesc& desc, const IDDesc& idDesc) {
 
     // We own one color value for each MSAA sample.
     int colorValuesPerPixel = SkTMax(1, fDesc.fSampleCnt);
-    if (fTexFBOID != fRTFBOID) {
+    if (fTexFBOID != kUnresolvableFBOID && fTexFBOID != fRTFBOID) {
         // If we own the resolve buffer then that is one more sample per pixel.
         colorValuesPerPixel += 1;
     } else if (fTexFBOID != 0) {