Add logging utility methods

Change-Id: I0f316830dcc0bbf438292a6d0fbe9f8154368500
diff --git a/libs/hwui/Matrix.h b/libs/hwui/Matrix.h
index 26cb05f..e33a001 100644
--- a/libs/hwui/Matrix.h
+++ b/libs/hwui/Matrix.h
@@ -209,7 +209,7 @@
 
     void decomposeScale(float& sx, float& sy) const;
 
-    void dump() const;
+    void dump(const char* label = NULL) const;
 
     static const Matrix4& identity();