frameworks/native: remove superfluous mention of SharedBuffer in Region.h

Towards deprecation of SharedBuffer

Change-Id: I9c853c86fb057280013405cb8c3c725e13175ea4
diff --git a/include/ui/Region.h b/include/ui/Region.h
index e9b3a0b..810f098 100644
--- a/include/ui/Region.h
+++ b/include/ui/Region.h
@@ -28,7 +28,6 @@
 namespace android {
 // ---------------------------------------------------------------------------
 
-class SharedBuffer;
 class String8;
 
 // ---------------------------------------------------------------------------