Don't use WebGL if there is a major performance caveat

src/ol/renderer/webgl/webglmaprenderer.js

@@ -88,6 +88,7 @@ ol.renderer.webgl.Map = function(container, map) {
   this.gl_ = ol.webgl.getContext(this.canvas_, {
     antialias: true,
     depth: false,
+    failIfMajorPerformanceCaveat: true,
     preserveDrawingBuffer: false,
     stencil: false
   });

src/ol/webgl/webgl.js

@@ -59,7 +59,9 @@ ol.webgl.SUPPORTED = (function() {
   try {
     var canvas = /** @type {HTMLCanvasElement} */
         (goog.dom.createElement(goog.dom.TagName.CANVAS));
-    return !goog.isNull(ol.webgl.getContext(canvas));
+    return !goog.isNull(ol.webgl.getContext(canvas, {
+      failIfMajorPerformanceCaveat: true
+    }));
   } catch (e) {
     return false;
   }