fix(material/slider): fix voiceover on ios (#27302)

* fix(material/slider): fix voiceover on ios

* fixes issue #15037

* fixup! fix(material/slider): fix voiceover on ios

* fixup! fix(material/slider): fix voiceover on ios

Author: wagnermaciel

src/material/slider/slider.spec.ts

@@ -90,48 +90,48 @@ describe('MDC-based MatSlider', () => {
     it('should set the default values', () => {
       expect(slider.min).toBe(0);
       expect(slider.max).toBe(100);
-      expect(slider.step).toBe(0);
-      checkInput(input, {min: 0, max: 100, value: 0, step: 0, translateX: 0});
+      expect(slider.step).toBe(1);
+      checkInput(input, {min: 0, max: 100, value: 0, step: 1, translateX: 0});
     });
 
     it('should update by click', fakeAsync(() => {
       setValueByClick(slider, input, 25);
-      checkInput(input, {min: 0, max: 100, value: 25, step: 0, translateX: 75});
+      checkInput(input, {min: 0, max: 100, value: 25, step: 1, translateX: 75});
 
       setValueByClick(slider, input, 50);
-      checkInput(input, {min: 0, max: 100, value: 50, step: 0, translateX: 150});
+      checkInput(input, {min: 0, max: 100, value: 50, step: 1, translateX: 150});
 
       setValueByClick(slider, input, 75);
-      checkInput(input, {min: 0, max: 100, value: 75, step: 0, translateX: 225});
+      checkInput(input, {min: 0, max: 100, value: 75, step: 1, translateX: 225});
 
       setValueByClick(slider, input, 100);
-      checkInput(input, {min: 0, max: 100, value: 100, step: 0, translateX: 300});
+      checkInput(input, {min: 0, max: 100, value: 100, step: 1, translateX: 300});
     }));
 
     it('should update by slide', fakeAsync(() => {
       slideToValue(slider, input, 25);
-      checkInput(input, {min: 0, max: 100, value: 25, step: 0, translateX: 75});
+      checkInput(input, {min: 0, max: 100, value: 25, step: 1, translateX: 75});
 
       slideToValue(slider, input, 50);
-      checkInput(input, {min: 0, max: 100, value: 50, step: 0, translateX: 150});
+      checkInput(input, {min: 0, max: 100, value: 50, step: 1, translateX: 150});
 
       slideToValue(slider, input, 75);
-      checkInput(input, {min: 0, max: 100, value: 75, step: 0, translateX: 225});
+      checkInput(input, {min: 0, max: 100, value: 75, step: 1, translateX: 225});
 
       slideToValue(slider, input, 100);
-      checkInput(input, {min: 0, max: 100, value: 100, step: 0, translateX: 300});
+      checkInput(input, {min: 0, max: 100, value: 100, step: 1, translateX: 300});
     }));
 
     it('should not slide before the track', fakeAsync(() => {
       slideToValue(slider, input, -10);
       expect(input.value).toBe(0);
-      checkInput(input, {min: 0, max: 100, value: 0, step: 0, translateX: 0});
+      checkInput(input, {min: 0, max: 100, value: 0, step: 1, translateX: 0});
     }));
 
     it('should not slide past the track', fakeAsync(() => {
       slideToValue(slider, input, 110);
       expect(input.value).toBe(100);
-      checkInput(input, {min: 0, max: 100, value: 100, step: 0, translateX: 300});
+      checkInput(input, {min: 0, max: 100, value: 100, step: 1, translateX: 300});
     }));
 
     // TODO(wagnermaciel): Fix this test case (behavior works as intended in browser).
@@ -140,7 +140,7 @@ describe('MDC-based MatSlider', () => {
     //   tick(200);
     //   fixture.detectChanges();
     //   setValueByClick(slider, input, 25);
-    //   checkInput(input, {min: 0, max: 100, value: 25, step: 0, translateX: 75});
+    //   checkInput(input, {min: 0, max: 100, value: 25, step: 1, translateX: 75});
     //   slider._elementRef.nativeElement.style.marginLeft = 'initial';
     // }));
   });
@@ -161,12 +161,12 @@ describe('MDC-based MatSlider', () => {
     }));
 
     it('should set the default values', () => {
-      checkInput(startInput, {min: 0, max: 100, value: 0, step: 0, translateX: 0});
-      checkInput(endInput, {min: 0, max: 100, value: 100, step: 0, translateX: 300});
+      checkInput(startInput, {min: 0, max: 100, value: 0, step: 1, translateX: 0});
+      checkInput(endInput, {min: 0, max: 100, value: 100, step: 1, translateX: 300});
 
       expect(slider.min).toBe(0);
       expect(slider.max).toBe(100);
-      expect(slider.step).toBe(0);
+      expect(slider.step).toBe(1);
     });
 
     it('should update by start input click', fakeAsync(() => {
@@ -1373,16 +1373,16 @@ describe('MDC-based MatSlider', () => {
     });
 
     it('should sync the value binding in both directions', fakeAsync(() => {
-      checkInput(input, {min: 0, max: 100, value: 0, step: 0, translateX: 0});
+      checkInput(input, {min: 0, max: 100, value: 0, step: 1, translateX: 0});
 
       slideToValue(slider, input, 10);
       expect(fixture.componentInstance.value).toBe(10);
-      checkInput(input, {min: 0, max: 100, value: 10, step: 0, translateX: 30});
+      checkInput(input, {min: 0, max: 100, value: 10, step: 1, translateX: 30});
 
       fixture.componentInstance.value = 20;
       fixture.detectChanges();
       expect(fixture.componentInstance.value).toBe(20);
-      checkInput(input, {min: 0, max: 100, value: 20, step: 0, translateX: 60});
+      checkInput(input, {min: 0, max: 100, value: 20, step: 1, translateX: 60});
     }));
   });
 

src/material/slider/slider.ts

@@ -283,7 +283,7 @@ export class MatSlider
       this._updateStep(step);
     }
   }
-  private _step: number = 0;
+  private _step: number = 1;
 
   private _updateStep(step: number): void {
     this._step = step;

src/material/slider/testing/slider-harness.spec.ts

@@ -96,7 +96,7 @@ describe('MDC-based MatSliderHarness', () => {
       await parallel(() => {
         return sliders.map(slider => slider.getStep());
       }),
-    ).toEqual([0, fixture.componentInstance.rangeSliderStep]);
+    ).toEqual([1, fixture.componentInstance.rangeSliderStep]);
   });
 
   it('should get the position of a slider thumb in a range slider', async () => {