Added video capture capabilities retrieval and caching to VideoCaptureManager

content/browser/renderer_host/media/video_capture_manager.h

Index: content/browser/renderer_host/media/video_capture_manager.h
diff --git a/content/browser/renderer_host/media/video_capture_manager.h b/content/browser/renderer_host/media/video_capture_manager.h
index 6f0b0ec4702dedd2e9e2f43caecee942542ec5e8..4e04772b4e31c377c007e61c43664b8520f1078f 100644
--- a/content/browser/renderer_host/media/video_capture_manager.h
+++ b/content/browser/renderer_host/media/video_capture_manager.h
@@ -17,6 +17,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/process/process_handle.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
@@ -59,7 +60,8 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   // Called by VideoCaptureHost to locate a capture device for |capture_params|,
   // adding the Host as a client of the device's controller if successful. The
   // value of |capture_params.session_id| controls which device is selected;
-  // this value should be a session id previously returned by Open().
+  // this value should be a session id previously returned by Open(). The device
+  // capabilities are reduced to |capture_params|.
   //
   // If the device is not already started (i.e., no other client is currently
   // capturing from this device), this call will cause a VideoCaptureController
@@ -82,9 +84,16 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
                             VideoCaptureControllerID client_id,
                             VideoCaptureControllerEventHandler* client_handler);
 
+  // Retrieve the available capture capabilities for a particular device. The
+  // capabilities are cached during device(s) enumeration and updated as clients
+  // open/close the device(s).
+  void GetDeviceCapabilities(int capture_session_id,
+                             media::VideoCaptureCapabilities* capabilities);
+
  private:
   virtual ~VideoCaptureManager();
   struct DeviceEntry;
+  struct DeviceInfo;
 
   // Check to see if |entry| has no clients left on its controller. If so,
   // remove it from the list of devices, and delete it asynchronously. |entry|
@@ -94,8 +103,12 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   // Helpers to report an event to our Listener.
   void OnOpened(MediaStreamType type, int capture_session_id);
   void OnClosed(MediaStreamType type, int capture_session_id);
-  void OnDevicesEnumerated(MediaStreamType stream_type,
-                           const media::VideoCaptureDevice::Names& names);
+  void OnDeviceNamesEnumerated(
+      MediaStreamType stream_type,
+      const media::VideoCaptureDevice::Names& names_snapshot);
+  void OnDeviceNameAndCapabilitiesEnumerated(
+      MediaStreamType stream_type,
+      const ScopedVector<DeviceInfo>& new_devices_info);
 
   // Find a DeviceEntry by its device ID and type, if it is already opened.
   DeviceEntry* GetDeviceEntryForMediaStreamDevice(
@@ -115,11 +128,16 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   media::VideoCaptureDevice::Names GetAvailableDevicesOnDeviceThread(
       MediaStreamType stream_type);
 
+  // Queries and returns the capabilities of all the devices in |device_names|.
+  ScopedVector<DeviceInfo> GetDevicesCapabilitiesOnDeviceThread(
+      const media::VideoCaptureDevice::Names& device_names);
+
   // Create and Start a new VideoCaptureDevice, storing the result in
   // |entry->video_capture_device|. Ownership of |client| passes to
   // the device.
   void DoStartDeviceOnDeviceThread(
       DeviceEntry* entry,
+      const media::VideoCaptureDevice::Name* device_name,
       const media::VideoCaptureCapability& capture_params,
       scoped_ptr<media::VideoCaptureDevice::Client> client);
 
@@ -127,6 +145,8 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   // |entry->video_capture_device|.
   void DoStopDeviceOnDeviceThread(DeviceEntry* entry);
 
+  DeviceInfo* FindDeviceInfoById(const std::string& id);
+
   // The message loop of media stream device thread, where VCD's live.
   scoped_refptr<base::MessageLoopProxy> device_loop_;
 
@@ -171,11 +191,27 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   // default. This is only used for the MEDIA_DEVICE_VIDEO_CAPTURE device type.
   bool use_fake_device_;
 
-  // We cache the enumerated video capture devices in
-  // GetAvailableDevicesOnDeviceThread() and then later look up the requested ID
-  // when a device is created in DoStartDeviceOnDeviceThread(). Used only on the
-  // device thread.
-  media::VideoCaptureDevice::Names video_capture_devices_;
+  // This struct is a convenient wrap of a devices' name and associated video
+  // capture capabilities.
+  struct DeviceInfo {
+    DeviceInfo();
+    DeviceInfo(const media::VideoCaptureDevice::Name& name,
+               const media::VideoCaptureCapabilities& capabilities);
+    ~DeviceInfo();
+
+    bool device_in_use_;
+    media::VideoCaptureCapability capability_in_use_;
+    media::VideoCaptureDevice::Name name_;
+    media::VideoCaptureCapabilities capabilities_;
+  };
+  // Local cache of the enumerated video capture devices' names and capture
+  // capabilities. The creation/update works as following: EnumeratedDevices()
+  // jumps to GetAvailableDevicesOnDeviceThread() and OnDeviceNamesEnumerated().
+  // From there, a posttask-reply GetDevicesCapabilitiesOnDeviceThread() and
+  // OnDeviceNameAndCapabilitiesEnumerated() is carried out. From the last one,
+  // the |listener_| OnDevicesEnumerated is called. The cache is only used in
+  // Browser::IO thread.
+  ScopedVector<DeviceInfo> devices_info_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };