Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/media_stream_manager.h

Index: content/browser/renderer_host/media/media_stream_manager.h
diff --git a/content/browser/renderer_host/media/media_stream_manager.h b/content/browser/renderer_host/media/media_stream_manager.h
index 17f863e90fda9b5140ee47983298bb4f17ac1026..97596eff6d19d93fa187d689e25cb905b601738b 100644
--- a/content/browser/renderer_host/media/media_stream_manager.h
+++ b/content/browser/renderer_host/media/media_stream_manager.h
@@ -30,19 +30,21 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/supports_user_data.h"
+#include "base/threading/thread.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/browser/renderer_host/media/media_stream_settings_requester.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/common/content_export.h"
+#include "content/public/browser/browser_thread.h"
+
+#if defined(OS_WIN)
+#include <objbase.h>  // For CoInitialize/CoUninitialize.
+#endif
 
 namespace content {
 class ResourceContext;
 }
 
-namespace media {
-class AudioManager;
-}
-
 namespace media_stream {
 
 class AudioInputDeviceManager;
@@ -50,6 +52,26 @@ class MediaStreamDeviceSettings;
 class MediaStreamRequester;
 class VideoCaptureManager;
 
+// Thread that enters STA on windows, and is base::thread on linux and mac.
+class DeviceThread : public base::Thread {
+ public:
+  explicit DeviceThread(const char *name) : base::Thread(name) {}

[tommi (sloooow) - chröme, 2012/07/02 13:36:36]

const char* name

[no longer working on chromium, 2012/07/04 12:35:25]

Done.

+
+ protected:
+#if defined(OS_WIN)
+  // Called just prior to starting the message loop.
+  virtual void Init() {
+    CoInitialize(NULL);

[tommi (sloooow) - chröme, 2012/07/02 13:36:36]

use the ScopedCOMInitializer class and remove the #if's

[no longer working on chromium, 2012/07/04 12:35:25]

Done.

+  }
+
+  // Called just after the message loop ends.
+  virtual void CleanUp() {
+    CoUninitialize();
+  }
+#endif
+  DISALLOW_COPY_AND_ASSIGN(DeviceThread);
+};
+
 // MediaStreamManager is used to generate and close new media devices, not to
 // start the media flow.
 // The classes requesting new media streams are answered using
@@ -62,10 +84,10 @@ class CONTENT_EXPORT MediaStreamManager
   // Returns the MediaStreamManager for the given ResourceContext. If it hasn't
   // been created yet, it will be constructed with the given AudioManager.
   static MediaStreamManager* GetForResourceContext(
-      content::ResourceContext* resource_context,
-      media::AudioManager* audio_manager);
+      content::ResourceContext* resource_context);
+
+  MediaStreamManager();
 
-  explicit MediaStreamManager(media::AudioManager* audio_manager);
   virtual ~MediaStreamManager();
 
   // Used to access VideoCaptureManager.
@@ -149,6 +171,12 @@ class CONTENT_EXPORT MediaStreamManager
   void StartEnumeration(DeviceRequest* new_request,
                         std::string* label);
 
+  // Helper to ensure the device thread before passing to device managers.
+  void EnsureDeviceThread();
+
+  // Device thread shared by VideoCaptureManager and AudioInputDeviceManager.
+  scoped_ptr<base::Thread> device_thread_;
+
   scoped_ptr<MediaStreamDeviceSettings> device_settings_;
   scoped_refptr<VideoCaptureManager> video_capture_manager_;
   scoped_refptr<AudioInputDeviceManager> audio_input_device_manager_;
@@ -160,7 +188,6 @@ class CONTENT_EXPORT MediaStreamManager
   // All non-closed request.
   typedef std::map<std::string, DeviceRequest> DeviceRequests;
   DeviceRequests requests_;
-  media::AudioManager* audio_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamManager);
 };