clean-up/simplify all dump() APIs

remove the scratch buffer parameter and use
String8::appendFormat() instead.

Change-Id: Ib96c91617c8e7292de87433d15cf6232b7d591b0
diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h
index 6c1b691..34264bf 100644
--- a/include/gui/BufferQueue.h
+++ b/include/gui/BufferQueue.h
@@ -229,7 +229,7 @@
 
     // dump our state in a String
     virtual void dump(String8& result) const;
-    virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const;
+    virtual void dump(String8& result, const char* prefix) const;
 
     // public facing structure for BufferSlot
     struct BufferItem {