Hook up the SequencedWorkerPool to the browser thread.

chrome/browser/visitedlink/visitedlink_master.cc

Index: chrome/browser/visitedlink/visitedlink_master.cc
===================================================================
--- chrome/browser/visitedlink/visitedlink_master.cc	(revision 117955)
+++ chrome/browser/visitedlink/visitedlink_master.cc	(working copy)
@@ -191,6 +191,7 @@
   history_service_override_ = NULL;
   suppress_rebuild_ = false;
   profile_ = profile;
+  sequence_token_ = BrowserThread::GetBlockingPool()->GetSequenceToken();
 
 #ifndef NDEBUG
   posted_asynchronous_operation_ = false;
@@ -242,6 +243,12 @@
   return AddFingerprint(fingerprint, true);
 }
 
+void VisitedLinkMaster::PostIOTask(const tracked_objects::Location& from_here,
+                                   const base::Closure& task) {
+  BrowserThread::GetBlockingPool()->PostSequencedWorkerTask(sequence_token_,
+                                                            from_here, task);
+}
+
 void VisitedLinkMaster::AddURL(const GURL& url) {
   Hash index = TryToAddURL(url);
   if (!table_builder_ && index != null_hash_) {
@@ -480,10 +487,7 @@
               hash_table_, table_length_ * sizeof(Fingerprint));
 
   // The hash table may have shrunk, so make sure this is the end.
-  BrowserThread::PostTask(
-      BrowserThread::FILE,
-      FROM_HERE,
-      base::Bind(base::IgnoreResult(&TruncateFile), file_));
+  PostIOTask(FROM_HERE, base::Bind(base::IgnoreResult(&TruncateFile), file_));
   return true;
 }
 
@@ -673,11 +677,7 @@
   }
   if (!file_)
     return;
-
-  BrowserThread::PostTask(
-      BrowserThread::FILE,
-      FROM_HERE,
-      base::Bind(base::IgnoreResult(&fclose), file_));
+  PostIOTask(FROM_HERE, base::Bind(base::IgnoreResult(&fclose), file_));
 }
 
 bool VisitedLinkMaster::ResizeTableIfNecessary() {
@@ -860,9 +860,7 @@
 #ifndef NDEBUG
   posted_asynchronous_operation_ = true;
 #endif
-
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
+  PostIOTask(FROM_HERE,
       base::Bind(&AsyncWrite, file, offset,
                  std::string(static_cast<const char*>(data), data_size)));
 }