When a surface is backed by an external render target force a copy on image snap

src/gpu/GrResourceCache.h

 
 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrResourceCache_DEFINED
 #define GrResourceCache_DEFINED
@@ skipping 193 matching lines @@
             fExternal = 0;
             fBorrowed = 0;
             fAdopted = 0;
             fUnbudgetedSize = 0;
         }
 
         void update(GrGpuResource* resource) {
             if (resource->cacheAccess().isScratch()) {
                 ++fScratch;
             }
-            if (resource->cacheAccess().isExternal()) {
+            if (resource->resourcePriv().isExternal()) {
                 ++fExternal;
             }
             if (resource->cacheAccess().isBorrowed()) {
                 ++fBorrowed;
             }
             if (resource->cacheAccess().isAdopted()) {
                 ++fAdopted;
             }
             if (!resource->resourcePriv().isBudgeted()) {
                 fUnbudgetedSize += resource->gpuMemorySize();
@@ skipping 206 matching lines @@
 
     friend class GrGpuResource; // To access all the proxy inline methods.
     friend class GrResourceCache; // To create this type.
 };
 
 inline GrResourceCache::ResourceAccess GrResourceCache::resourceAccess() {
     return ResourceAccess(this);
 }
 
 #endif