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

src/gpu/gl/GrGLRenderTarget.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLRenderTarget.h"
 
 #include "GrGLGpu.h"
@@ skipping 22 matching lines @@
     fMSColorRenderbufferID  = idDesc.fMSColorRenderbufferID;
     fRTLifecycle            = idDesc.fLifeCycle;
 
     fViewport.fLeft   = 0;
     fViewport.fBottom = 0;
     fViewport.fWidth  = desc.fWidth;
     fViewport.fHeight = desc.fHeight;
 
     // 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) {
         // For auto-resolving FBOs, the MSAA buffer is free.
         colorValuesPerPixel = 1;
     }
     SkASSERT(kUnknown_GrPixelConfig != fDesc.fConfig);
     SkASSERT(!GrPixelConfigIsCompressed(fDesc.fConfig));
     size_t colorBytes = GrBytesPerPixel(fDesc.fConfig);
     SkASSERT(colorBytes > 0);
@@ skipping 21 matching lines @@
     fMSColorRenderbufferID  = 0;
     INHERITED::onRelease();
 }
 
 void GrGLRenderTarget::onAbandon() {
     fRTFBOID                = 0;
     fTexFBOID               = 0;
     fMSColorRenderbufferID  = 0;
     INHERITED::onAbandon();
 }