fix [3385504] Surface flinger hang when adding dim surface

Change-Id: I8e0cda414bcad5854d2ca5dde8370bfd8b2e5ea4
diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index 1a34f52..8ed4749 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -285,6 +285,7 @@
     virtual ~LayerBaseClient();
 
             sp<Surface> getSurface();
+            wp<IBinder> getSurfaceBinder() const;
     virtual sp<Surface> createSurface() const;
     virtual sp<LayerBaseClient> getLayerBaseClient() const {
         return const_cast<LayerBaseClient*>(this); }
@@ -325,6 +326,7 @@
 private:
     mutable Mutex mLock;
     mutable wp<Surface> mClientSurface;
+    wp<IBinder> mClientSurfaceBinder;
     const wp<Client> mClientRef;
     // only read
     const uint32_t mIdentity;