Enable clang for libui/libgui/surfaceflinger

Enables clang and C++11 for libui/libgui/surfaceflinger, and
eliminates all compile-time warnings.

Change-Id: Ie237fdb5ae44f2bfcddaa884f9c65ec3f08ae50f
(cherry picked from commit f10c46ef855b6410b20ebd8b1351d4d78d8eca8e)
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index 0fab7e2..2c14d6d 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -86,8 +86,7 @@
     virtual status_t compositionComplete();
     virtual status_t advanceFrame();
     virtual void onFrameCommitted();
-    using BBinder::dump;
-    virtual void dump(String8& result) const;
+    virtual void dumpAsString(String8& result) const;
     virtual void resizeBuffers(const uint32_t w, const uint32_t h);
 
 private: