Fixed example that relied on internal class.

examples/webgl_shaders_tonemapping.html

@@ -350,8 +350,6 @@
 
 				container.appendChild( renderer.domElement );
 
-				var extensions = new THREE.WebGLExtensions( renderer.getContext() );
-
 				// var width = window.innerWidth || 1;
 				var height = window.innerHeight || 1;
 
@@ -359,7 +357,7 @@
 				var regularRenderTarget = new THREE.WebGLRenderTarget( windowThirdX, height, parameters );
 				ldrEffectComposer = new THREE.EffectComposer( renderer, regularRenderTarget );
 
-				if ( extensions.get('OES_texture_half_float_linear') ) {
+				if ( renderer.extensions.get('OES_texture_half_float_linear') ) {
 					parameters.type = THREE.FloatType;
 				}
 				var hdrRenderTarget = new THREE.WebGLRenderTarget( windowThirdX, height, parameters );