Don't allow direct access to StreamString's internal buffer.

This is a large API change that removes the two functions from
StreamString that return a std::string& and a const std::string&,
and instead provide one function which returns a StringRef.

Direct access to the underlying buffer violates the concept of
a "stream" which is intended to provide forward only access,
and makes porting to llvm::raw_ostream more difficult in the
future.

Differential Revision: https://reviews.llvm.org/D26698

llvm-svn: 287152

lldb/source/Plugins/Language/Java/JavaFormatterFunctions.cpp

@@ -70,7 +70,7 @@ public:
     DataExtractor data(buffer_sp, process_sp->GetByteOrder(),
                        process_sp->GetAddressByteSize());
     return CreateValueObjectFromData(
-        name.GetData(), data, valobj->GetExecutionContextRef(), element_type);
+        name.GetString(), data, valobj->GetExecutionContextRef(), element_type);
   }
 
   bool Update() override { return false; }