clean-up/simplify all dump() APIs

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

Change-Id: Ib96c91617c8e7292de87433d15cf6232b7d591b0
diff --git a/services/surfaceflinger/EventThread.h b/services/surfaceflinger/EventThread.h
index 1934f98..f6bd676 100644
--- a/services/surfaceflinger/EventThread.h
+++ b/services/surfaceflinger/EventThread.h
@@ -84,7 +84,7 @@
     Vector< sp<EventThread::Connection> > waitForEvent(
             DisplayEventReceiver::Event* event);
 
-    void dump(String8& result, char* buffer, size_t SIZE) const;
+    void dump(String8& result) const;
 
 private:
     virtual bool        threadLoop();