More JDWP robustness.

We pass a lot more JDWP tests with this (fewer total failures than dalvik,
because although dalvik implements more requests, it assumes that the debuggers
only send it valid input).

I've also added some of the missing constants (there are tests of modifier 12,
SourceNameMatch, which was added in Java 6).

Change-Id: I502e87b50fb305c5c8b061421339c8ceab104640
diff --git a/src/hprof/hprof.h b/src/hprof/hprof.h
index e999dce..7c1180e 100644
--- a/src/hprof/hprof.h
+++ b/src/hprof/hprof.h
@@ -212,7 +212,7 @@
   // Otherwise, "file_name_" must be valid, though if "fd" >= 0 it will
   // only be used for debug messages.
   bool direct_to_ddms_;
-  char* file_name_;
+  std::string file_name_;
   char* file_data_ptr_;   // for open_memstream
   size_t file_data_size_; // for open_memstream
   FILE *mem_fp_;