Allow ol.style.Stroke#width to be undefined

src/ol/render/canvas/canvasimmediate.js

@@ -278,7 +278,7 @@ ol.render.canvas.Immediate.prototype.setFillStrokeStyle =
   if (!ol.style.stroke.equals(state.strokeStyle, strokeStyle)) {
     if (goog.isDefAndNotNull(strokeStyle)) {
       context.strokeStyle = ol.color.asString(strokeStyle.color);
-      context.lineWidth = strokeStyle.width;
+      context.lineWidth = goog.isDef(strokeStyle.width) ? strokeStyle.width : 1;
     }
     state.strokeStyle = strokeStyle;
   }

src/ol/render/canvas/canvasreplay.js

@@ -145,7 +145,7 @@ ol.render.canvas.Replay.prototype.draw = function(context, transform) {
       goog.asserts.assert(goog.isObject(instruction[1]));
       var strokeStyle = /** @type {ol.style.Stroke} */ (instruction[1]);
       context.strokeStyle = ol.color.asString(strokeStyle.color);
-      context.lineWidth = strokeStyle.width;
+      context.lineWidth = goog.isDef(strokeStyle.width) ? strokeStyle.width : 1;
       ++i;
     } else if (type == ol.render.canvas.Instruction.STROKE) {
       context.stroke();

src/ol/shape.js

@@ -37,7 +37,7 @@ ol.shape.renderCircle = function(radius, fillStyle, strokeStyle) {
   }
   if (goog.isDefAndNotNull(strokeStyle)) {
     context.strokeStyle = ol.color.asString(strokeStyle.color);
-    context.lineWidth = strokeStyle.width;
+    context.lineWidth = goog.isDef(strokeStyle.width) ? strokeStyle.width : 1;
     context.stroke();
   }