Replace RunInSeries() and RunInParallel() with CallbackSeries helper class.

media/base/callback_util.h

Index: media/base/callback_util.h
diff --git a/media/base/callback_util.h b/media/base/callback_util.h
index d831191c88b3ae162a6ddc5b7113fd41fe707ce2..42321eaf2674c6a58ae66c2344b66db948fe841a 100644
--- a/media/base/callback_util.h
+++ b/media/base/callback_util.h
@@ -8,45 +8,52 @@
 #include <queue>
 
 #include "base/callback.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "media/base/pipeline_status.h"
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace media {
 
-typedef base::Callback<void(const base::Closure&)> ClosureFunc;
+// Why the odd looking typedef? SerialCallbackRunner requires callbacks to

[Ami GONE FROM CHROMIUM, 2012/08/03 19:29:01]

This comment doesn't explain *why* SCR would want such a thing.
It might be clearer to name this something closer to its use than its type; WDYT
of BoundPipelineStatusCB?

[scherkus (not reviewing), 2012/08/03 20:19:04]

Done although I'm sad at losing our funk

+// functions that accept a PipelineStatusCB, not PipelineStatusCBs themselves.
 typedef base::Callback<void(const PipelineStatusCB&)> PipelineStatusCBFunc;

[Ami GONE FROM CHROMIUM, 2012/08/03 19:29:01]

This typedef belongs at the top of the public: section of SCR.

[scherkus (not reviewing), 2012/08/03 20:19:04]

Done.

[scherkus (not reviewing), 2012/08/03 20:19:04]

Done.

 
-// Executes the closures in FIFO order, executing |done_cb| when the last
-// closure has completed running.
-//
-// All closures (including |done_cb|) are executed on same thread as the
-// calling thread.
-void RunInSeries(scoped_ptr<std::queue<ClosureFunc> > closures,
-                 const base::Closure& done_cb);
-
-// Executes the closures in FIFO order, executing |done_cb| when the last
-// closure has completed running, reporting the final status code.
-//
-// Closures will stop being executed if a previous closure in the series
-// returned an error status and |done_cb| will be executed prematurely.
-//
-// All closures (including |done_cb|) are executed on same thread as the
-// calling thread.
-void RunInSeriesWithStatus(
-    scoped_ptr<std::queue<PipelineStatusCBFunc> > status_cbs,
-    const PipelineStatusCB& done_cb);
-
-// Executes the closures in parallel, executing |done_cb| when all closures have
-// completed running.
-//
-// No attempt is made to parallelize execution of the closures. In other words,
-// this method will run all closures in FIFO order if said closures execute
-// synchronously on the same call stack.
-//
-// All closures (including |done_cb|) are executed on same thread as the
-// calling thread.
-void RunInParallel(scoped_ptr<std::queue<ClosureFunc> > closures,
-                   const base::Closure& done_cb);
+class SerialCallbackRunner {
+ public:
+  // Executes callbacks in |status_cbs| in series, executing |done_cb| when

[Ami GONE FROM CHROMIUM, 2012/08/03 19:29:01]

s/callbacks in/bound functions from/ ?

[scherkus (not reviewing), 2012/08/03 20:19:04]

Done.

+  // finished.
+  //
+  // All callbacks are executed on the thread that Run() is called on, including
+  // |done_cb|.
+  //
+  // Deleting the object will prevent execution of any unstarted callbacks,
+  // including |done_cb|.
+  static scoped_ptr<SerialCallbackRunner> Run(
+      scoped_ptr<std::queue<PipelineStatusCBFunc> > status_cbs,
+      const PipelineStatusCB& done_cb);
+
+ private:
+  friend class scoped_ptr<SerialCallbackRunner>;
+
+  SerialCallbackRunner(
+      scoped_ptr<std::queue<PipelineStatusCBFunc> > status_cbs,
+      const PipelineStatusCB& done_cb);
+  ~SerialCallbackRunner();
+
+  void RunNextInSeries(PipelineStatus last_status);
+
+  base::WeakPtrFactory<SerialCallbackRunner> weak_this_;
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
+  scoped_ptr<std::queue<PipelineStatusCBFunc> > status_cbs_;
+  PipelineStatusCB done_cb_;
+
+  DISALLOW_COPY_AND_ASSIGN(SerialCallbackRunner);
+};
 
 }  // namespace media