Remove the AudioManager singleton.

Unit tests now instantiate their own AudioManager and can choose to
use the default one or provide their own mock implementation without
having to worry about conflicting with the singleton.

The teardown sequence of the AudioManager and its thread has been cleaned
up significantly and I don't think it has been completely tested before as
the audio thread was terminated before all objects that belonged to the
thread had a chance to do cleanup.  The AudioManager unit tests do not use
the actual audio thread, so this part seems to have been left out.

In Chrome, the AudioManager instance is now owned by BrowserProcessImpl
and always constructed on the UI thread.  This instance is then shared
in the same way that several other 'manager' type objects are shared to
'content' code, via content::ResourceContext.  Audio specific classes
do though receive a direct pointer to the AudioManager and are required
to do proper reference counting if they need to hold onto the instance.
I chose to use the ResourceContext rather than direct use of g_browser_process
to avoid requiring another singleton when writing relatively simple tests
that touch the AudioManager.

I added a couple of safeguards to guard against future regressions:
- Not more than one instance of the AudioManager should be created.
- The AudioManager should not be addrefed by its own thread.  This
  can basically become a circular reference and prevent deterministic
  shutdown.

Reviewers:  Of course you're free to review everything,
but here's the breakdown in terms of the bare minimum from
the standpoint of "Owners approval".  I'm asking Henrik to be the
main reviewer of the entire patch (sorry!).

Henrik: Everything minus the below, but it would be great if you could
        take a look at the whole thing, specifically media/audio.

Pawel:  I'd like you to take a generic look at this approach.
        The key areas as far as the singleton itself goes are in
        media/audio/audio_manager[_base].* and
        chrome/browser/browser_process*.*

Satish: content/browser/speech/*
        media/audio/audio_manager_base.* (new reference counting code)

Andrew: content/browser/renderer_host/media/*
        content/renderer/media/webrtc_audio_device_unittest.cc (Owner)

Avi:    content/browser/renderer_host/render_process_host_impl.cc
        content/browser/resource_context.*

William: chrome/browser/profiles/profile_io_data.cc
	 chrome/browser/browser_process*.*

Robert:  This is basically a heads up. I hope that I didn't break the OpenBSD
         implementation, but unfortunately I have no way of knowing for sure.

Shijing: Please take a look at AudioManagerLinux.  I replaced the set of
         active streams with a simple counter.

BUG=105249
TEST=content_unittests, media_unittests, browser_tests.
Review URL: http://codereview.chromium.org/8818012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114084 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 23 insertions, 28 deletions

diff --git a/content/browser/speech/speech_input_browsertest.cc b/content/browser/speech/speech_input_browsertest.cc
index 7dd1f9f..f0c6321 100644
--- a/content/browser/speech/speech_input_browsertest.cc
+++ b/content/browser/speech/speech_input_browsertest.cc
@@ -49,16 +49,13 @@ class FakeSpeechInputManager : public SpeechInputManager {
   }
 
   // SpeechInputManager methods.
-  virtual void StartRecognition(Delegate* delegate,
-                                int caller_id,
-                                int render_process_id,
-                                int render_view_id,
-                                const gfx::Rect& element_rect,
-                                const std::string& language,
-                                const std::string& grammar,
-                                const std::string& origin_url,
-                                net::URLRequestContextGetter* context_getter,
-                                SpeechInputPreferences* speech_input_prefs) {
+  virtual void StartRecognition(Delegate* delegate, int caller_id,
+      int render_process_id, int render_view_id, const gfx::Rect& element_rect,
+      const std::string& language, const std::string& grammar,
+      const std::string& origin_url,
+      net::URLRequestContextGetter* context_getter,
+      SpeechInputPreferences* speech_input_prefs,
+      AudioManager* audio_manager) OVERRIDE {
     VLOG(1) << "StartRecognition invoked.";
     EXPECT_EQ(0, caller_id_);
     EXPECT_EQ(NULL, delegate_);
@@ -77,18 +74,18 @@ class FakeSpeechInputManager : public SpeechInputManager {
           base::Unretained(this)));
     }
   }
-  virtual void CancelRecognition(int caller_id) {
+  virtual void CancelRecognition(int caller_id) OVERRIDE {
     VLOG(1) << "CancelRecognition invoked.";
     EXPECT_EQ(caller_id_, caller_id);
     caller_id_ = 0;
     delegate_ = NULL;
   }
-  virtual void StopRecording(int caller_id) {
+  virtual void StopRecording(int caller_id) OVERRIDE {
     VLOG(1) << "StopRecording invoked.";
     EXPECT_EQ(caller_id_, caller_id);
     // Nothing to do here since we aren't really recording.
   }
-  virtual void CancelAllRequestsWithDelegate(Delegate* delegate) {
+  virtual void CancelAllRequestsWithDelegate(Delegate* delegate) OVERRIDE {
     VLOG(1) << "CancelAllRequestsWithDelegate invoked.";
     // delegate_ is set to NULL if a fake result was received (see below), so
     // check that delegate_ matches the incoming parameter only when there is
@@ -98,23 +95,21 @@ class FakeSpeechInputManager : public SpeechInputManager {
   }
 
  protected:
-  virtual void GetRequestInfo(bool* can_report_metrics,
-                              std::string* request_info) {}
-  virtual void ShowRecognitionRequested(int caller_id,
-                                        int render_process_id,
-                                        int render_view_id,
-                                        const gfx::Rect& element_rect) {}
-  virtual void ShowWarmUp(int caller_id) {}
-  virtual void ShowRecognizing(int caller_id) {}
-  virtual void ShowRecording(int caller_id)  {}
-  virtual void ShowInputVolume(int caller_id,
-                               float volume,
-                               float noise_volume) {}
+  virtual void GetRequestInfo(AudioManager* audio_manager,
+      bool* can_report_metrics,
+      std::string* request_info) OVERRIDE {}
+  virtual void ShowRecognitionRequested(int caller_id, int render_process_id,
+      int render_view_id, const gfx::Rect& element_rect) OVERRIDE {}
+  virtual void ShowWarmUp(int caller_id) OVERRIDE {}
+  virtual void ShowRecognizing(int caller_id) OVERRIDE {}
+  virtual void ShowRecording(int caller_id) OVERRIDE {}
+  virtual void ShowInputVolume(int caller_id, float volume,
+      float noise_volume) OVERRIDE {}
   virtual void ShowMicError(int caller_id,
-                            SpeechInputManager::MicError error) {}
+      SpeechInputManager::MicError error) OVERRIDE {}
   virtual void ShowRecognizerError(int caller_id,
-                                   content::SpeechInputError error) {}
-  virtual void DoClose(int caller_id) {}
+      content::SpeechInputError error) OVERRIDE {}
+  virtual void DoClose(int caller_id) OVERRIDE {}
 
  private:
   void SetFakeRecognitionResult() {