Add --trace-rotate-startup-file option and store unsaved trace data on exit.

content/browser/browser_shutdown_profile_dumper.h

Index: content/browser/browser_shutdown_profile_dumper.h
diff --git a/content/browser/browser_shutdown_profile_dumper.h b/content/browser/browser_shutdown_profile_dumper.h
index f98a32cb9ca98d0dc42f5a0973bb541349b3bb8e..2d22ee76eb1eb7b158c26a0c8951c70137959bf5 100644
--- a/content/browser/browser_shutdown_profile_dumper.h
+++ b/content/browser/browser_shutdown_profile_dumper.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_memory.h"
 #include "content/common/content_export.h"
@@ -29,19 +30,16 @@ namespace content {
 // |SequencedWorkerPool| will get killed in the shutdown process.
 class BrowserShutdownProfileDumper {
  public:
-  BrowserShutdownProfileDumper();
+  explicit BrowserShutdownProfileDumper(const base::FilePath& dump_file_name);
 
   ~BrowserShutdownProfileDumper();
 
  private:
   // Writes all traces which happened to disk.
-  void WriteTracesToDisc(const base::FilePath& file_name);
+  void WriteTracesToDisc();
 
   void EndTraceAndFlush(base::WaitableEvent* flush_complete_event);
 
-  // Returns the file name where we should save the trace dump to.
-  base::FilePath GetFileName();
-
   // The callback for the |TraceLog::Flush| function. It saves all traces to
   // disc.
   void WriteTraceDataCollected(
@@ -61,6 +59,9 @@ class BrowserShutdownProfileDumper {
   // Closes the dump file.
   void CloseFile();
 
+  // The name of the dump file.
+  base::FilePath dump_file_name_;
+
   // The number of blocks we have already written.
   int blocks_;
   // For dumping the content to disc.