Add support for creating texture backed images where Skia will delete the texture.

src/image/SkSurface_Gpu.cpp

Index: src/image/SkSurface_Gpu.cpp
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index 20fcbf333e52ba7e050f780807a919131b327f44..0db3e8cecaecc85de373222090b4afb3fd3c204b 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -109,7 +109,8 @@ SkSurface* SkSurface::NewWrappedRenderTarget(GrContext* context, GrBackendTextur
     if (!SkToBool(desc.fFlags & kRenderTarget_GrBackendTextureFlag)) {
         return NULL;
     }
-    SkAutoTUnref<GrSurface> surface(context->textureProvider()->wrapBackendTexture(desc));
+    SkAutoTUnref<GrSurface> surface(context->textureProvider()->wrapBackendTexture(desc,
+                                    kBorrow_GrWrapOwnership));
     if (!surface) {
         return NULL;
     }