comments only: update docs for SkStream::readData(), SkWStream::writeData()

include/core/SkStream.h

Index: include/core/SkStream.h
===================================================================
--- include/core/SkStream.h	(revision 8258)
+++ include/core/SkStream.h	(working copy)
@@ -73,8 +73,8 @@
     size_t   readPackedUInt();
 
     /**
-     *  Create a new SkData from the stream contents. This balances the call
-     *  SkWStream::writeData().
+     *  Reconstitute an SkData object that was written to the stream
+     *  using SkWStream::writeData().
      */
     SkData* readData();
 
@@ -115,6 +115,14 @@
 
     bool writeStream(SkStream* input, size_t length);
 
+    /**
+     * Append an SkData object to the stream, such that it can be read
+     * out of the stream using SkStream::readData().
+     *
+     * Note that the encoding method used to write the SkData object
+     * to the stream may change over time.  This method DOES NOT
+     * just write the raw content of the SkData object to the stream.
+     */
     bool writeData(const SkData*);
 };