fix(progress-circle): allow value to be set to 0 (#1536)

Author: andrewseguin

src/lib/progress-circle/progress-circle.spec.ts

@@ -66,6 +66,12 @@ describe('MdProgressCircular', () => {
     progressComponent.value = 50;
     expect(progressComponent.value).toBe(50);
 
+    progressComponent.value = 0;
+    expect(progressComponent.value).toBe(0);
+
+    progressComponent.value = 100;
+    expect(progressComponent.value).toBe(100);
+
     progressComponent.value = 999;
     expect(progressComponent.value).toBe(100);
 

src/lib/progress-circle/progress-circle.ts

@@ -108,7 +108,7 @@ export class MdProgressCircle implements OnDestroy {
     }
   }
   set value(v: number) {
-    if (v && this.mode == 'determinate') {
+    if (v != null && this.mode == 'determinate') {
       let newValue = clamp(v);
       this._animateCircle((this.value || 0), newValue, linearEase, DURATION_DETERMINATE, 0);
       this._value = newValue;