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.cpp b/services/surfaceflinger/EventThread.cpp
index 4d0fc79..4126c8a 100644
--- a/services/surfaceflinger/EventThread.cpp
+++ b/services/surfaceflinger/EventThread.cpp
@@ -320,7 +320,7 @@
     mDebugVsyncEnabled = false;
 }
 
-void EventThread::dump(String8& result, char* buffer, size_t SIZE) const {
+void EventThread::dump(String8& result) const {
     Mutex::Autolock _l(mLock);
     result.appendFormat("VSYNC state: %s\n",
             mDebugVsyncEnabled?"enabled":"disabled");