surfaceflinger: add support for gralloc dump hooks

Change-Id: Ib6f539ed0132b70d040d653c03d52cc04249ac3c
diff --git a/include/ui/FramebufferNativeWindow.h b/include/ui/FramebufferNativeWindow.h
index 2cd0911..16117ad 100644
--- a/include/ui/FramebufferNativeWindow.h
+++ b/include/ui/FramebufferNativeWindow.h
@@ -23,6 +23,7 @@
 #include <EGL/egl.h>
 
 #include <utils/threads.h>
+#include <utils/String8.h>
 #include <ui/Rect.h>
 
 #include <pixelflinger/pixelflinger.h>
@@ -56,7 +57,9 @@
     bool isUpdateOnDemand() const { return mUpdateOnDemand; }
     status_t setUpdateRectangle(const Rect& updateRect);
     status_t compositionComplete();
-    
+
+    void dump(String8& result);
+
     // for debugging only
     int getCurrentBufferIndex() const;