Fix a regression in resize behavior from #147 (#149)

The problem was that I was using `canvas.getBoundingClientRect()` to get the size to resize to, but that was changing as the result of CSS properties set on the canvas! Instead, we take the measurements of its container now which is set to fill the screen, and the canvas has its size entirely managed by `graphics.ts`.

src/views/application.tsx

@@ -186,11 +186,20 @@ export class GLCanvas extends Component<GLCanvasProps, void> {
     this.props.setGLCanvas(this.canvas)
   }
 
+  private container: HTMLElement | null = null
+  private containerRef = (container?: Element) => {
+    if (container instanceof HTMLElement) {
+      this.container = container
+    } else {
+      this.container = null
+    }
+  }
+
   private maybeResize = () => {
-    if (!this.canvas) return
+    if (!this.container) return
     if (!this.props.canvasContext) return
 
-    let {width, height} = this.canvas.getBoundingClientRect()
+    let {width, height} = this.container.getBoundingClientRect()
 
     const widthInAppUnits = width
     const heightInAppUnits = height
@@ -210,16 +219,13 @@ export class GLCanvas extends Component<GLCanvasProps, void> {
     if (this.props.canvasContext) {
       this.props.canvasContext.requestFrame()
     }
-    window.addEventListener('resize', this.onWindowResize)
   }
   componentWillReceiveProps(nextProps: GLCanvasProps) {
     if (this.props.canvasContext !== nextProps.canvasContext) {
       if (this.props.canvasContext) {
-        console.log('a')
         this.props.canvasContext.removeBeforeFrameHandler(this.maybeResize)
       }
       if (nextProps.canvasContext) {
-        console.log('b')
         nextProps.canvasContext.addBeforeFrameHandler(this.maybeResize)
         nextProps.canvasContext.requestFrame()
       }
@@ -235,7 +241,11 @@ export class GLCanvas extends Component<GLCanvasProps, void> {
     window.removeEventListener('resize', this.onWindowResize)
   }
   render() {
-    return <canvas className={css(style.glCanvasView)} ref={this.ref} width={1} height={1} />
+    return (
+      <div ref={this.containerRef} className={css(style.glCanvasView)}>
+        <canvas ref={this.ref} width={1} height={1} />
+      </div>
+    )
   }
 }