Initial version of external_oes texture support and unit test

src/gpu/GrResourceProvider.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrResourceProvider.h"
 
 #include "GrGpu.h"
@@ skipping 184 matching lines @@
             // Need to try and create a new stencil
             stencil = this->gpu()->createStencilAttachmentForRenderTarget(rt, width, height);
             if (stencil) {
                 stencil->resourcePriv().setUniqueKey(sbKey);
                 newStencil = true;
             }
         }
         if (rt->renderTargetPriv().attachStencilAttachment(stencil)) {
             if (newStencil) {
                 // Right now we're clearing the stencil attachment here after it is
-                // attached to an RT for the first time. When we start matching
+                // attached to a RT for the first time. When we start matching
                 // stencil buffers with smaller color targets this will no longer
                 // be correct because it won't be guaranteed to clear the entire
                 // sb.
                 // We used to clear down in the GL subclass using a special purpose
                 // FBO. But iOS doesn't allow a stencil-only FBO. It reports unsupported
                 // FBO status.
                 this->gpu()->clearStencil(rt);
             }
         }
     }
     return rt->renderTargetPriv().getStencilAttachment();
 }