Allow stencils to be attached to render targets created via SkSurface::MakeFromBackendTextureAsRend…

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 141 matching lines @@
     fMSColorRenderbufferID  = 0;
     INHERITED::onAbandon();
 }
 
 GrGLGpu* GrGLRenderTarget::getGLGpu() const {
     SkASSERT(!this->wasDestroyed());
     return static_cast<GrGLGpu*>(this->getGpu());
 }
 
 bool GrGLRenderTarget::canAttemptStencilAttachment() const {
-    // When we have not created the FBO ID we do not attempt to modify its attachments.
-    // Direct GrGLRenderTarget instances are always created with CreateWrapped.
-    SkASSERT(this->resourcePriv().refsWrappedObjects());
-    return false;
+    // Only modify the FBO's attachments if we have created the FBO. Public APIs do not currently
+    // allow for borrowed FBO ownership, so we can safely assume that if an object is owned,
+    // Skia created it.
+    return this->fRTFBOOwnership == GrBackendObjectOwnership::kOwned;
 }
 
 void GrGLRenderTarget::dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const {
     // Don't log the backing texture's contribution to the memory size. This will be handled by the
     // texture object.
 
     // Log any renderbuffer's contribution to memory. We only do this if we own the renderbuffer
     // (have a fMSColorRenderbufferID).
     if (fMSColorRenderbufferID) {
         size_t size = this->msaaSamples() * this->totalBytesPerSample();
@@ skipping 41 matching lines @@
 int GrGLRenderTarget::totalSamples() const {
   int total_samples = this->msaaSamples();
 
   if (fTexFBOID != kUnresolvableFBOID) {
       // If we own the resolve buffer then that is one more sample per pixel.
       total_samples += 1;
   }
 
   return total_samples;
 }