Do not open file on UI thread in VisitedLinkMaster

chrome/browser/visitedlink/visitedlink_master.h

Index: chrome/browser/visitedlink/visitedlink_master.h
===================================================================
--- chrome/browser/visitedlink/visitedlink_master.h	(revision 145483)
+++ chrome/browser/visitedlink/visitedlink_master.h	(working copy)
@@ -117,8 +117,8 @@
 
   // Call to cause the entire database file to be re-written from scratch
   // to disk. Used by the performance tester.
-  bool RewriteFile() {
-    return WriteFullTable();
+  void RewriteFile() {
+    WriteFullTable();
   }
 #endif
 
@@ -130,6 +130,8 @@
   // Object to rebuild the table on the history thread (see the .cc file).
   class TableBuilder;
 
+  typedef FILE* FilePtr;

[brettw, 2012/07/27 22:11:14]

I think I prefer just seeing FILE** in the various places since then there's
nothing to look up what it means. So I'd probably delete this. Can you also add
that this class owns the pointer.

+
   // Byte offsets of values in the header.
   static const int32 kFileHeaderSignatureOffset;
   static const int32 kFileHeaderVersionOffset;
@@ -169,9 +171,9 @@
   void PostIOTask(const tracked_objects::Location& from_here,
                   const base::Closure& task);
 
-  // Writes the entire table to disk, returning true on success. It will leave
-  // the table file open and the handle to it in file_
-  bool WriteFullTable();
+  // Writes the entire table to disk. It will leave the table file open and
+  // the handle to it will be stored in file_.
+  void WriteFullTable();
 
   // Try to load the table from the database file. If the file doesn't exist or
   // is corrupt, this will return failure.
@@ -192,7 +194,7 @@
 
   // Wrapper around Window's WriteFile using asynchronous I/O. This will proxy
   // the write to a background thread.
-  void WriteToFile(FILE* hfile, off_t offset, void* data, int32 data_size);
+  void WriteToFile(FilePtr* hfile, off_t offset, void* data, int32 data_size);
 
   // Helper function to schedule and asynchronous write of the used count to
   // disk (this is a common operation).
@@ -339,7 +341,7 @@
   // The currently open file with the table in it. This may be NULL if we're
   // rebuilding and haven't written a new version yet. Writing to the file may
   // be safely ignored in this case.
-  FILE* file_;
+  FilePtr* file_;

[brettw, 2012/07/27 22:11:14]

Can you clarify the comment here? There are now three cases, file_ is NULL
(rebuilding and haven't written a new version as in the old comment), and that
it exists but points to NULL (because it's being opened on a background thread).

 
   // Shared memory consists of a SharedHeader followed by the table.
   base::SharedMemory *shared_memory_;