Bug 1484783 - Ensure to read the default stride when hardware acceleration isn't usable. r=mattwoodrow

On some platforms where a hardware decoder is present, but non functioning, we would fail to initialize the video stride, leading to the frames being incorrectly displayed later.

Also delete the DXVA2 manager early under those circumstances

Differential Revision: https://phabricator.services.mozilla.com/D5402

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

dom/media/platforms/wmf/WMFVideoMFTManager.cpp

@@ -637,7 +637,6 @@ WMFVideoMFTManager::InitInternal()
       if (SUCCEEDED(hr)) {
         mUseHwAccel = true;
       } else {
-        DeleteOnMainThread(mDXVA2Manager);
         mDXVAFailureReason = nsPrintfCString(
           "MFT_MESSAGE_SET_D3D_MANAGER failed with code %X", hr);
       }
@@ -649,6 +648,12 @@ WMFVideoMFTManager::InitInternal()
   }
 
   if (!mUseHwAccel) {
+    if (mDXVA2Manager) {
+      // Either mDXVAEnabled was set to false prior the second call to
+      // InitInternal() due to CanUseDXVA() returning false, or
+      // MFT_MESSAGE_SET_D3D_MANAGER failed
+      DeleteOnMainThread(mDXVA2Manager);
+    }
     if (mStreamType == VP9 || mStreamType == VP8) {
       return MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR,
                          RESULT_DETAIL("Use VP8/9 MFT only if HW acceleration "
@@ -680,7 +685,7 @@ WMFVideoMFTManager::InitInternal()
   LOG("Video Decoder initialized, Using DXVA: %s",
       (mUseHwAccel ? "Yes" : "No"));
 
-  if (mDXVA2Manager) {
+  if (mUseHwAccel) {
     hr = mDXVA2Manager->ConfigureForSize(mVideoInfo.ImageRect().width,
                                          mVideoInfo.ImageRect().height);
     NS_ENSURE_TRUE(SUCCEEDED(hr),