Add MessageLoop::AssertIdle(). Use in ChromeOS audio threads.

BUG=chrome-os:11110
TEST=existing

Review URL: http://codereview.chromium.org/6374010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72576 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 11 insertions, 2 deletions

diff --git a/base/message_loop.cc b/base/message_loop.cc
index 518a0fd..d83adcc 100644
--- a/base/message_loop.cc
+++ b/base/message_loop.cc
@@ -286,6 +286,12 @@ void MessageLoop::RemoveTaskObserver(TaskObserver* task_observer) {
   task_observers_.RemoveObserver(task_observer);
 }
 
+void MessageLoop::AssertIdle() const {
+  // We only check |incoming_queue_|, since we don't want to lock |work_queue_|.
+  base::AutoLock lock(incoming_queue_lock_);
+  DCHECK(incoming_queue_.empty());
+}
+
 //------------------------------------------------------------------------------
 
 // Runs the loop in two different SEH modes:
diff --git a/base/message_loop.h b/base/message_loop.h
index 7a3af6e..d238997 100644
--- a/base/message_loop.h
+++ b/base/message_loop.h
@@ -315,6 +315,9 @@ class MessageLoop : public base::MessagePump::Delegate {
   // for at least 1s.
   static const int kHighResolutionTimerModeLeaseTimeMs = 1000;
 
+  // Asserts that the MessageLoop is "idle".
+  void AssertIdle() const;
+
   //----------------------------------------------------------------------------
  protected:
   struct RunState {
@@ -461,12 +464,12 @@ class MessageLoop : public base::MessagePump::Delegate {
   scoped_refptr<base::Histogram> message_histogram_;
 
   // A null terminated list which creates an incoming_queue of tasks that are
-  // aquired under a mutex for processing on this instance's thread. These tasks
+  // acquired under a mutex for processing on this instance's thread. These tasks
   // have not yet been sorted out into items for our work_queue_ vs items that
   // will be handled by the TimerManager.
   TaskQueue incoming_queue_;
   // Protect access to incoming_queue_.
-  base::Lock incoming_queue_lock_;
+  mutable base::Lock incoming_queue_lock_;
 
   RunState* state_;