ART: dex2oat flag for HGraphVisualizer dump file

This patch adds a new '--dump-cfg=<file>' flag to dex2oat which
specifies the file that HGraphVisualizer will store its output into.
Until now the graph was dumped to 'art.cfg' in the current working
directory. To make Checker work with run-test, the output directory
needs to be customizable.

Change-Id: I4a940f7708b88deea5a0e51d13aed13e52199349
diff --git a/compiler/driver/compiler_driver.h b/compiler/driver/compiler_driver.h
index 7ddc32c..11b4329 100644
--- a/compiler/driver/compiler_driver.h
+++ b/compiler/driver/compiler_driver.h
@@ -97,6 +97,7 @@
                           bool image, std::set<std::string>* image_classes,
                           std::set<std::string>* compiled_classes,
                           size_t thread_count, bool dump_stats, bool dump_passes,
+                          const std::string& dump_cfg_file_name,
                           CumulativeLogger* timer, int swap_fd,
                           const std::string& profile_file);
 
@@ -371,6 +372,10 @@
     return dump_passes_;
   }
 
+  const std::string& GetDumpCfgFileName() const {
+    return dump_cfg_file_name_;
+  }
+
   CumulativeLogger* GetTimingsLogger() const {
     return timings_logger_;
   }
@@ -542,6 +547,7 @@
 
   bool dump_stats_;
   const bool dump_passes_;
+  const std::string& dump_cfg_file_name_;
 
   CumulativeLogger* const timings_logger_;