Revert 116816 - Hook up the SequencedWorkerPool to the browser thread.

This does some refactoring of the static data in the browser thread so we only have one global object instead of a bunch fo separate arrays.

It also hooks up the visited link master's I/O to use this new system as a proof of concept.
Review URL: http://codereview.chromium.org/9065009

TBR=brettw@chromium.org
Review URL: http://codereview.chromium.org/9122022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@116817 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 53 deletions

diff --git a/base/threading/sequenced_worker_pool.cc b/base/threading/sequenced_worker_pool.cc
index 0a3697b..05ccff1 100644
--- a/base/threading/sequenced_worker_pool.cc
+++ b/base/threading/sequenced_worker_pool.cc
@@ -57,31 +57,20 @@ class SequencedWorkerPool::Inner
   Inner(size_t max_threads, const std::string& thread_name_prefix);
   virtual ~Inner();
 
+  // Backends for SequenceWorkerPool.
   SequenceToken GetSequenceToken();
-
   SequenceToken GetNamedSequenceToken(const std::string& name);
-
-  // This function accepts a name and an ID. If the name is null, the
-  // token ID is used. This allows us to implement the optional name lookup
-  // from a single function without having to enter the lock a separate time.
-  bool PostTask(const std::string* optional_token_name,
-                int sequence_token_id,
+  bool PostTask(int sequence_token_id,
                 SequencedWorkerPool::WorkerShutdown shutdown_behavior,
                 const tracked_objects::Location& from_here,
                 const base::Closure& task);
-
   void Shutdown();
-
   void SetTestingObserver(SequencedWorkerPool::TestingObserver* observer);
 
   // Runs the worker loop on the background thread.
   void ThreadLoop(Worker* this_worker);
 
  private:
-  // Called from within the lock, this converts the given token name into a
-  // token ID, creating a new one if necessary.
-  int LockedGetNamedTokenID(const std::string& name);
-
   // The calling code should clear the given delete_these_oustide_lock
   // vector the next time the lock is released. See the implementation for
   // a more detailed description.
@@ -246,11 +235,18 @@ SequencedWorkerPool::SequenceToken
 SequencedWorkerPool::Inner::GetNamedSequenceToken(
     const std::string& name) {
   base::AutoLock lock(lock_);
-  return SequenceToken(LockedGetNamedTokenID(name));
+  std::map<std::string, int>::const_iterator found =
+      named_sequence_tokens_.find(name);
+  if (found != named_sequence_tokens_.end())
+    return SequenceToken(found->second);  // Got an existing one.
+
+  // Create a new one for this name.
+  SequenceToken result = GetSequenceToken();
+  named_sequence_tokens_.insert(std::make_pair(name, result.id_));
+  return result;
 }
 
 bool SequencedWorkerPool::Inner::PostTask(
-    const std::string* optional_token_name,
     int sequence_token_id,
     SequencedWorkerPool::WorkerShutdown shutdown_behavior,
     const tracked_objects::Location& from_here,
@@ -267,10 +263,6 @@ bool SequencedWorkerPool::Inner::PostTask(
     if (terminating_)
       return false;
 
-    // Now that we have the lock, apply the named token rules.
-    if (optional_token_name)
-      sequenced.sequence_token_id = LockedGetNamedTokenID(*optional_token_name);
-
     pending_tasks_.push_back(sequenced);
     pending_task_count_++;
     if (shutdown_behavior == BLOCK_SHUTDOWN)
@@ -385,22 +377,6 @@ void SequencedWorkerPool::Inner::ThreadLoop(Worker* this_worker) {
   cond_var_.Signal();
 }
 
-int SequencedWorkerPool::Inner::LockedGetNamedTokenID(
-    const std::string& name) {
-  lock_.AssertAcquired();
-  DCHECK(!name.empty());
-
-  std::map<std::string, int>::const_iterator found =
-      named_sequence_tokens_.find(name);
-  if (found != named_sequence_tokens_.end())
-    return found->second;  // Got an existing one.
-
-  // Create a new one for this name.
-  SequenceToken result = GetSequenceToken();
-  named_sequence_tokens_.insert(std::make_pair(name, result.id_));
-  return result.id_;
-}
-
 bool SequencedWorkerPool::Inner::GetWork(
     SequencedTask* task,
     std::vector<base::Closure>* delete_these_outside_lock) {
@@ -617,38 +593,30 @@ SequencedWorkerPool::SequenceToken SequencedWorkerPool::GetNamedSequenceToken(
 bool SequencedWorkerPool::PostWorkerTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task) {
-  return inner_->PostTask(NULL, 0, BLOCK_SHUTDOWN, from_here, task);
+  return inner_->PostTask(0, BLOCK_SHUTDOWN, from_here, task);
 }
 
 bool SequencedWorkerPool::PostWorkerTaskWithShutdownBehavior(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     WorkerShutdown shutdown_behavior) {
-  return inner_->PostTask(NULL, 0, shutdown_behavior, from_here, task);
+  return inner_->PostTask(0, shutdown_behavior, from_here, task);
 }
 
 bool SequencedWorkerPool::PostSequencedWorkerTask(
     SequenceToken sequence_token,
     const tracked_objects::Location& from_here,
     const base::Closure& task) {
-  return inner_->PostTask(NULL, sequence_token.id_, BLOCK_SHUTDOWN,
+  return inner_->PostTask(sequence_token.id_, BLOCK_SHUTDOWN,
                           from_here, task);
 }
 
-bool SequencedWorkerPool::PostNamedSequencedWorkerTask(
-    const std::string& token_name,
-    const tracked_objects::Location& from_here,
-    const base::Closure& task) {
-  DCHECK(!token_name.empty());
-  return inner_->PostTask(&token_name, 0, BLOCK_SHUTDOWN, from_here, task);
-}
-
 bool SequencedWorkerPool::PostSequencedWorkerTaskWithShutdownBehavior(
     SequenceToken sequence_token,
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     WorkerShutdown shutdown_behavior) {
-  return inner_->PostTask(NULL, sequence_token.id_, shutdown_behavior,
+  return inner_->PostTask(sequence_token.id_, shutdown_behavior,
                           from_here, task);
 }
 
diff --git a/base/threading/sequenced_worker_pool.h b/base/threading/sequenced_worker_pool.h
index 71e431c..c6e0560 100644
--- a/base/threading/sequenced_worker_pool.h
+++ b/base/threading/sequenced_worker_pool.h
@@ -172,12 +172,6 @@ class BASE_EXPORT SequencedWorkerPool {
                                const tracked_objects::Location& from_here,
                                const base::Closure& task);
 
-  // Like PostSequencedWorkerTask above, but allows you to specify a named
-  // token, which saves an extra call to GetNamedSequenceToken.
-  bool PostNamedSequencedWorkerTask(const std::string& token_name,
-                                    const tracked_objects::Location& from_here,
-                                    const base::Closure& task);
-
   // Same as PostSequencedWorkerTask but allows specification of the shutdown
   // behavior.
   bool PostSequencedWorkerTaskWithShutdownBehavior(