[ANGLE] Support EGL_PLATFORM_WAYLAND_EXT extension

WebGL fails to initialize EGL display with followingn error:
ERR: Display.cpp:1083 (initialize): ANGLE Display::initialize error 12289: Failed to get system egl display

Author: asurdej-comcast

Source/ThirdParty/ANGLE/src/libANGLE/renderer/gl/egl/FunctionsEGL.cpp

@@ -43,6 +43,7 @@ bool IsValidPlatformTypeForPlatformDisplayConnection(EGLAttrib platformType)
     switch (platformType)
     {
         case EGL_PLATFORM_SURFACELESS_MESA:
+        case EGL_PLATFORM_WAYLAND_EXT:
             return true;
         default:
             break;
@@ -420,6 +421,10 @@ EGLDisplay FunctionsEGL::getPlatformDisplay(EGLAttrib platformType,
             if (!hasExtension("EGL_MESA_platform_surfaceless"))
                 return EGL_NO_DISPLAY;
             break;
+        case EGL_PLATFORM_WAYLAND_EXT:
+            if (!hasExtension("EGL_EXT_platform_wayland"))
+                return EGL_NO_DISPLAY;
+            break;
         default:
             UNREACHABLE();
             return EGL_NO_DISPLAY;