make SkDeviceFactory reference counted



git-svn-id: http://skia.googlecode.com/svn/trunk@1180 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index ff1bb0d..15def87 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -121,6 +121,9 @@
     virtual void makeRenderTargetCurrent();
 
 protected:
+    // override
+    virtual SkDeviceFactory* onNewDeviceFactory();
+
     class TexCache;
     TexCache* lockCachedTexture(const SkBitmap& bitmap,
                                 const GrSamplerState& sampler,