clean-up/simplify all dump() APIs

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

Change-Id: Ib96c91617c8e7292de87433d15cf6232b7d591b0
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 739099c..d387a60 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -385,12 +385,13 @@
      * Debugging & dumpsys
      */
     void listLayersLocked(const Vector<String16>& args, size_t& index,
-        String8& result, char* buffer, size_t SIZE) const;
+        String8& result) const;
     void dumpStatsLocked(const Vector<String16>& args, size_t& index,
-        String8& result, char* buffer, size_t SIZE) const;
+        String8& result) const;
     void clearStatsLocked(const Vector<String16>& args, size_t& index,
-        String8& result, char* buffer, size_t SIZE);
-    void dumpAllLocked(String8& result, char* buffer, size_t SIZE) const;
+        String8& result);
+    void dumpAllLocked(const Vector<String16>& args, size_t& index,
+        String8& result) const;
     bool startDdmConnection();
     static void appendSfConfigString(String8& result);