Bug 1443181 - If ANGLE D3D11 disabled, ask for D3D9 explicitly. r=lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D37351

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

gfx/gl/GLLibraryEGL.cpp

@@ -279,8 +279,6 @@ AngleErrorReporting gAngleErrorReporter;
 
 static EGLDisplay GetAndInitDisplayForAccelANGLE(
     GLLibraryEGL& egl, nsACString* const out_failureId) {
-  EGLDisplay ret = 0;
-
   if (wr::RenderThread::IsInRenderThread()) {
     return GetAndInitDisplayForWebRender(egl, EGL_DEFAULT_DISPLAY);
   }
@@ -304,16 +302,21 @@ static EGLDisplay GetAndInitDisplayForAccelANGLE(
     //       will live longer than the ANGLE display so we're fine.
   });
 
-  if (gfxConfig::IsForcedOnByUser(Feature::D3D11_HW_ANGLE)) {
-    return GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ONLY_DISPLAY_ANGLE);
-  }
-
+  EGLDisplay ret = nullptr;
   if (d3d11ANGLE.IsEnabled()) {
-    ret = GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE);
+    ret = egl.fGetDisplay(
+        EGL_DEFAULT_DISPLAY);  // This will try d3d11, then d3d9.
+  } else {
+    // D3D9-only.
+    const EGLint attribs[] = {LOCAL_EGL_PLATFORM_ANGLE_TYPE_ANGLE,
+                              LOCAL_EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE,
+                              LOCAL_EGL_NONE};
+    ret = egl.fGetPlatformDisplayEXT(LOCAL_EGL_PLATFORM_ANGLE_ANGLE,
+                                     EGL_DEFAULT_DISPLAY, attribs);
   }
 
-  if (!ret) {
-    ret = GetAndInitDisplay(egl, EGL_DEFAULT_DISPLAY);
+  if (ret && !egl.fInitialize(ret, nullptr, nullptr)) {
+    ret = nullptr;
   }
 
   if (!ret && out_failureId->IsEmpty()) {