Implement missing safelyRun() on ThreadedRenderer

Change-Id: I14b75f37a13fabaa759a51369190dbdc84087c4b
diff --git a/libs/hwui/renderthread/CanvasContext.h b/libs/hwui/renderthread/CanvasContext.h
index 2daa905..3197df3 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -65,6 +65,8 @@
     void attachFunctor(Functor* functor);
     void detachFunctor(Functor* functor);
 
+    void runWithGlContext(RenderTask* task);
+
 private:
     void setSurface(EGLNativeWindowType window);
     void swapBuffers();