Implement device enumeration for PPB_VideoCapture_Dev.

- Implement PPB_VideoCapture_Dev v0.2.
- Use a ref-counted PlatformVideoCapture to manage lifespan of media::VideoCapture::EventHandler, instead of manipulating the ref count of PPB_VideoCapture_Impl.
- Extend examples/video_capture.

BUG=None
TEST=examples/video_capture

Review URL: https://chromiumcodereview.appspot.com/9234064

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122176 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 69 insertions, 21 deletions

diff --git a/ppapi/c/dev/ppb_video_capture_dev.h b/ppapi/c/dev/ppb_video_capture_dev.h
index 396879c..5a48725 100644
--- a/ppapi/c/dev/ppb_video_capture_dev.h
+++ b/ppapi/c/dev/ppb_video_capture_dev.h
@@ -3,20 +3,22 @@
  * found in the LICENSE file.
  */
 
-/* From dev/ppb_video_capture_dev.idl modified Tue Oct 11 10:01:39 2011. */
+/* From dev/ppb_video_capture_dev.idl modified Wed Feb 15 12:15:46 2012. */
 
 #ifndef PPAPI_C_DEV_PPB_VIDEO_CAPTURE_DEV_H_
 #define PPAPI_C_DEV_PPB_VIDEO_CAPTURE_DEV_H_
 
 #include "ppapi/c/dev/pp_video_capture_dev.h"
 #include "ppapi/c/pp_bool.h"
+#include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 
 #define PPB_VIDEOCAPTURE_DEV_INTERFACE_0_1 "PPB_VideoCapture(Dev);0.1"
-#define PPB_VIDEOCAPTURE_DEV_INTERFACE PPB_VIDEOCAPTURE_DEV_INTERFACE_0_1
+#define PPB_VIDEOCAPTURE_DEV_INTERFACE_0_2 "PPB_VideoCapture(Dev);0.2"
+#define PPB_VIDEOCAPTURE_DEV_INTERFACE PPB_VIDEOCAPTURE_DEV_INTERFACE_0_2
 
 /**
  * @file
@@ -33,18 +35,22 @@
  *
  * Theory of operation:
  * 1- Create a VideoCapture resource using Create.
- * 2- Start the capture using StartCapture. You pass in the requested info
+ * 2- Find available video capture devices using EnumerateDevices.
+ * 3- Open a video capture device. In addition to a device reference (0 can be
+ * used to indicate the default device), you pass in the requested info
  * (resolution, frame rate), as well as suggest a number of buffers you will
  * need.
- * 3- Receive the OnDeviceInfo callback, in PPP_VideoCapture_Dev, which will
+ * 4- Start the capture using StartCapture.
+ * 5- Receive the OnDeviceInfo callback, in PPP_VideoCapture_Dev, which will
  * give you the actual capture info (the requested one is not guaranteed), as
  * well as an array of buffers allocated by the browser.
- * 4- On every frame captured by the browser, OnBufferReady (in
+ * 6- On every frame captured by the browser, OnBufferReady (in
  * PPP_VideoCapture_Dev) is called with the index of the buffer from the array
  * containing the new frame. The buffer is now "owned" by the plugin, and the
  * browser won't reuse it until ReuseBuffer is called.
- * 5- When the plugin is done with the buffer, call ReuseBuffer
- * 6- Stop the capture using StopCapture.
+ * 7- When the plugin is done with the buffer, call ReuseBuffer.
+ * 8- Stop the capture using StopCapture.
+ * 9- Close the device.
  *
  * The browser may change the resolution based on the constraints of the system,
  * in which case OnDeviceInfo will be called again, with new buffers.
@@ -53,7 +59,7 @@
  * 4:2:0, one byte per pixel, tightly packed (width x height Y values, then
  * width/2 x height/2 U values, then width/2 x height/2 V values).
  */
-struct PPB_VideoCapture_Dev_0_1 {
+struct PPB_VideoCapture_Dev_0_2 {
   /**
    * Creates a new VideoCapture.
    */
@@ -63,22 +69,46 @@ struct PPB_VideoCapture_Dev_0_1 {
    */
   PP_Bool (*IsVideoCapture)(PP_Resource video_capture);
   /**
-   * Starts the capture. |requested_info| is a pointer to a structure containing
-   * the requested resolution and frame rate. |buffer_count| is the number of
-   * buffers requested by the plugin. Note: it is only used as advisory, the
-   * browser may allocate more of fewer based on available resources.
-   * How many buffers depends on usage. At least 2 to make sure latency doesn't
-   * cause lost frames. If the plugin expects to hold on to more than one buffer
-   * at a time (e.g. to do multi-frame processing, like video encoding), it
-   * should request that many more.
+   * Enumerates video capture devices. Once the operation is completed
+   * successfully, |devices| will be set to a PPB_ResourceArray_Dev resource,
+   * which holds a list of PPB_DeviceRef_Dev resources.
+   *
+   * Please note that:
+   * - this method ignores the previous value pointed to by |devices| (won't
+   *   release reference even if it is not 0);
+   * - |devices| must be valid until |callback| is called, if the method
+   *   returns PP_OK_COMPLETIONPENDING;
+   * - the ref count of the returned |devices| has already been increased by 1
+   *   for the caller.
+   */
+  int32_t (*EnumerateDevices)(PP_Resource video_capture,
+                              PP_Resource* devices,
+                              struct PP_CompletionCallback callback);
+  /**
+   * Opens a video capture device. |device_ref| identifies a video capture
+   * device. It could be one of the resource in the array returned by
+   * |EnumerateDevices()|, or 0 which means the default device.
+   * |requested_info| is a pointer to a structure containing the requested
+   * resolution and frame rate. |buffer_count| is the number of buffers
+   * requested by the plugin. Note: it is only used as advisory, the browser may
+   * allocate more or fewer based on available resources. How many buffers
+   * depends on usage. At least 2 to make sure latency doesn't cause lost
+   * frames. If the plugin expects to hold on to more than one buffer at a time
+   * (e.g. to do multi-frame processing, like video encoding), it should request
+   * that many more.
+   */
+  int32_t (*Open)(PP_Resource video_capture,
+                  PP_Resource device_ref,
+                  const struct PP_VideoCaptureDeviceInfo_Dev* requested_info,
+                  uint32_t buffer_count,
+                  struct PP_CompletionCallback callback);
+  /**
+   * Starts the capture.
    *
    * Returns PP_ERROR_FAILED if called when the capture was already started, or
    * PP_OK on success.
    */
-  int32_t (*StartCapture)(
-      PP_Resource video_capture,
-      const struct PP_VideoCaptureDeviceInfo_Dev* requested_info,
-      uint32_t buffer_count);
+  int32_t (*StartCapture)(PP_Resource video_capture);
   /**
    * Allows the browser to reuse a buffer that was previously sent by
    * PPP_VideoCapture_Dev.OnBufferReady. |buffer| is the index of the buffer in
@@ -96,9 +126,27 @@ struct PPB_VideoCapture_Dev_0_1 {
    * success.
    */
   int32_t (*StopCapture)(PP_Resource video_capture);
+  /**
+   * Closes the video capture device, and stops capturing if necessary. It is
+   * not valid to call |Open()| again after a call to this method.
+   * If a video capture resource is destroyed while a device is still open, then
+   * it will be implicitly closed, so you are not required to call this method.
+   */
+  void (*Close)(PP_Resource video_capture);
 };
 
-typedef struct PPB_VideoCapture_Dev_0_1 PPB_VideoCapture_Dev;
+typedef struct PPB_VideoCapture_Dev_0_2 PPB_VideoCapture_Dev;
+
+struct PPB_VideoCapture_Dev_0_1 {
+  PP_Resource (*Create)(PP_Instance instance);
+  PP_Bool (*IsVideoCapture)(PP_Resource video_capture);
+  int32_t (*StartCapture)(
+      PP_Resource video_capture,
+      const struct PP_VideoCaptureDeviceInfo_Dev* requested_info,
+      uint32_t buffer_count);
+  int32_t (*ReuseBuffer)(PP_Resource video_capture, uint32_t buffer);
+  int32_t (*StopCapture)(PP_Resource video_capture);
+};
 /**
  * @}
  */