Bug 1581806 - Trigger devicechange event for audio and video input devices only. r=dminor

After Bug 1581193 devicechange notifications were triggered with any device change, not just video and audio devices. This patch limits down the notifications to only video and audio input devices change.

Differential Revision: https://phabricator.services.mozilla.com/D46147

--HG--
extra : moz-landing-system : lando

media/webrtc/trunk/webrtc/modules/video_capture/windows/device_info_ds.cc

@@ -16,10 +16,25 @@
 #include "rtc_base/stringutils.h"
 
 #include <dvdmedia.h>
+#include <Dbt.h>
+#include <ks.h>
+#include <ksmedia.h>
 
 namespace webrtc {
 namespace videocapturemodule {
 
+BOOL isCaptureDevice(DEV_BROADCAST_HDR *pHdr)
+{
+  if (pHdr == NULL) {
+    return FALSE;
+  }
+  if (pHdr->dbch_devicetype != DBT_DEVTYP_DEVICEINTERFACE) {
+    return FALSE;
+  }
+  DEV_BROADCAST_DEVICEINTERFACE* pDi = (DEV_BROADCAST_DEVICEINTERFACE*)pHdr;
+  return pDi->dbcc_classguid == KSCATEGORY_CAPTURE;
+}
+
 LRESULT CALLBACK WndProc(HWND hWnd, UINT uiMsg, WPARAM wParam, LPARAM lParam)
 {
     DeviceInfoDS* pParent;
@@ -35,7 +50,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uiMsg, WPARAM wParam, LPARAM lParam)
     else if (uiMsg == WM_DEVICECHANGE)
     {
         pParent = (DeviceInfoDS*)GetWindowLongPtr(hWnd, GWLP_USERDATA);
-        if (pParent)
+        if (pParent && isCaptureDevice((PDEV_BROADCAST_HDR)lParam))
         {
             pParent->DeviceChange();
         }
@@ -56,7 +71,8 @@ DeviceInfoDS* DeviceInfoDS::Create() {
 DeviceInfoDS::DeviceInfoDS()
     : _dsDevEnum(NULL),
       _dsMonikerDevEnum(NULL),
-      _CoUninitializeIsRequired(true) {
+      _CoUninitializeIsRequired(true),
+      _hdevnotify(NULL) {
   // 1) Initialize the COM library (make Windows load the DLLs).
   //
   // CoInitializeEx must be called at least once, and is usually called only
@@ -110,6 +126,14 @@ DeviceInfoDS::DeviceInfoDS()
     _hwnd = CreateWindow(_wndClass.lpszClassName, NULL, 0, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL,
                          NULL, _hInstance, this);
+
+    DEV_BROADCAST_DEVICEINTERFACE di = { 0 };
+    di.dbcc_size = sizeof(di);
+    di.dbcc_devicetype  = DBT_DEVTYP_DEVICEINTERFACE;
+    di.dbcc_classguid  = KSCATEGORY_CAPTURE;
+
+    _hdevnotify = RegisterDeviceNotification(_hwnd, &di,
+                                             DEVICE_NOTIFY_WINDOW_HANDLE);
   }
 }
 
@@ -119,6 +143,10 @@ DeviceInfoDS::~DeviceInfoDS() {
   if (_CoUninitializeIsRequired) {
     CoUninitialize();
   }
+  if (_hdevnotify)
+  {
+    UnregisterDeviceNotification(_hdevnotify);
+  }
   if (_hwnd != NULL) {
     DestroyWindow(_hwnd);
   }

media/webrtc/trunk/webrtc/modules/video_capture/windows/device_info_ds.h

@@ -96,6 +96,7 @@ class DeviceInfoDS : public DeviceInfoImpl {
   HWND _hwnd;
   WNDCLASS _wndClass;
   HINSTANCE _hInstance;
+  HDEVNOTIFY _hdevnotify;
 };
 }  // namespace videocapturemodule
 }  // namespace webrtc