fix(gestures): fixes scroll issue with hammer config

Fixes scroll issue with hammer config where pinch/rotate gestures are preventing the screen from scrolling.

Closes #6897

src/config/providers.ts

@@ -1,6 +1,7 @@
 import { enableProdMode, PLATFORM_DIRECTIVES, provide } from '@angular/core';
 import { disableDeprecatedForms, provideForms } from '@angular/forms';
 import { HTTP_PROVIDERS } from '@angular/http';
+import { HAMMER_GESTURE_CONFIG } from '@angular/platform-browser';
 
 import { ActionSheetController } from '../components/action-sheet/action-sheet';
 import { AlertController } from '../components/alert/alert';
@@ -10,6 +11,7 @@ import { closest, nativeTimeout } from '../util/dom';
 import { Events } from '../util/events';
 import { FeatureDetect } from '../util/feature-detect';
 import { Form } from '../util/form';
+import { IonicGestureConfig } from '../gestures/ionic-gesture-config';
 import { GestureController } from '../gestures/gesture-controller';
 import { IONIC_DIRECTIVES } from './directives';
 import { isPresent } from '../util/util';
@@ -81,6 +83,8 @@ export function ionicProviders(customProviders?: Array<any>, config?: any): any[
     Translate,
   ];
 
+  providers.push( {provide: HAMMER_GESTURE_CONFIG, useClass: IonicGestureConfig} );
+
   if (isPresent(customProviders)) {
     providers.push(customProviders);
   }

src/gestures/ionic-gesture-config.ts

@@ -0,0 +1,25 @@
+import {Injectable} from '@angular/core';
+import {HammerGestureConfig} from '@angular/platform-browser';
+
+/* this class override the default angular gesture config.
+ * The motivation for this is enabling pinch, rotate or
+ * any other multi-touch gestures block scrolling.
+ */
+
+/**
+ * @private
+ */
+@Injectable()
+export class IonicGestureConfig extends HammerGestureConfig {
+  
+  buildHammer(element: HTMLElement) {
+    var mc = new (<any> window).Hammer(element);
+
+    for (let eventName in this.overrides) {
+      mc.get(eventName).set(this.overrides[eventName]);
+    }
+
+    return mc;
+  }
+
+}

src/gestures/test/ionic-gesture-config.spec.ts

@@ -0,0 +1,31 @@
+import { IonicGestureConfig } from '../../../src/gestures/ionic-gesture-config';
+
+export function run() {
+
+  describe('IonicGestureConfig', () => {
+    it('should create a new instance of hammer', () => {
+      // arrange
+      let instance = new IonicGestureConfig();
+      let expectedParam = { name: "expectedParam"};
+      let expectedHammerInstance = { name: "hammer"};
+      
+      let actualParam : any = null;
+      let callCount = 0;
+
+      (<any> window).Hammer = (param: any) => {
+        callCount++;
+        actualParam = param;
+        return expectedHammerInstance;
+      };
+      
+      // act
+      let returnValue = instance.buildHammer( <HTMLElement> <any> expectedParam);
+
+      // assert
+      expect(returnValue.name).toEqual(expectedHammerInstance.name);
+      expect(callCount).toEqual(1);
+      expect(actualParam.name).toEqual(expectedParam.name);
+    });
+  })
+
+}