TS: Added missing multiView files.

src/renderers/WebGLMultiviewRenderTarget.d.ts

@@ -0,0 +1,17 @@
+import {
+	WebGLRenderTarget,
+	WebGLRenderTargetOptions,
+} from './WebGLRenderTarget';
+
+export class WebGLMultiviewRenderTarget extends WebGLRenderTarget {
+
+	constructor(
+		width: number,
+		height: number,
+		numViews: number,
+		options?: WebGLRenderTargetOptions
+	);
+
+	setNumViews( numViews: number ): this;
+
+}

src/renderers/webgl/WebGLBackground.d.ts

@@ -1,10 +1,10 @@
 
-import { Color } from "../../math/Color.js";
-import { WebGLRenderer } from "../WebGLRenderer.js";
-import { WebGLState } from "./WebGLState.js";
-import { WebGLObjects } from "./WebGLObjects.js";
-import { WebGLRenderLists } from "./WebGLRenderLists.js";
-import { Scene } from "../../scenes/Scene.js";
+import { Color } from '../../math/Color';
+import { WebGLRenderer } from '../WebGLRenderer';
+import { WebGLState } from './WebGLState';
+import { WebGLObjects } from './WebGLObjects';
+import { WebGLRenderLists } from './WebGLRenderLists';
+import { Scene } from '../../scenes/Scene';
 
 export class WebGLBackground {
 

src/renderers/webgl/WebGLMultiview.d.ts

@@ -0,0 +1,17 @@
+import { Camera } from './../../cameras/Camera';
+import { Object3D } from './../../core/Object3D';
+import { WebGLRenderer } from '../WebGLRenderer';
+import { WebGLUniforms } from './WebGLUniforms';
+
+export class WebGLMultiview {
+
+	constructor( renderer: WebGLRenderer, gl: WebGLRenderingContext );
+
+	isAvailable(): boolean;
+	attachCamera( camera: Camera ): void;
+	detachCamera( camera: Camera ): void;
+	updateCameraProjectionMatricesUniform( camera: Camera, uniforms: WebGLUniforms ): void;
+	updateCameraViewMatricesUniform( camera: Camera, uniforms: WebGLUniforms ): void;
+	updateObjectMatricesUniforms( object: Object3D, camera: Camera, uniforms: WebGLUniforms ): void;
+
+}