Fix tslint and mobile safari and firefox

Author: tinayuangao

src/lib/core/overlay/position/viewport-ruler.ts

@@ -50,12 +50,8 @@ export class ViewportRuler {
     // `scrollTop` and `scrollLeft` is inconsistent. However, using the bounding rect of
     // `document.documentElement` works consistently, where the `top` and `left` values will
     // equal negative the scroll position.
-    const top =  documentRect.top < 0 && document.body.scrollTop == 0 ?
-        -documentRect.top :
-        document.body.scrollTop;
-    const left = documentRect.left < 0 && document.body.scrollLeft == 0 ?
-        -documentRect.left :
-        document.body.scrollLeft;
+    const top = -documentRect.top || document.body.scrollTop || window.scrollY || 0;
+    const left = -documentRect.left || document.body.scrollLeft || window.scrollX || 0;
 
     return {top, left};
   }

src/lib/core/ripple/ripple.spec.ts

@@ -196,6 +196,11 @@ describe('MdRipple', () => {
       document.body.appendChild(veryLargeElement);
       document.body.scrollTop = pageScrollTop;
       document.body.scrollLeft = pageScrollLeft;
+      // Firefox
+      document.documentElement.scrollLeft = pageScrollLeft;
+      document.documentElement.scrollTop = pageScrollTop;
+      // Mobile safari
+      window.scrollTo(pageScrollLeft, pageScrollTop);
 
       rippleElement.style.position = 'absolute';
       rippleElement.style.left = `${elementLeft}px`;

src/lib/core/ripple/ripple.ts

@@ -15,7 +15,7 @@ import {
   ForegroundRipple,
   ForegroundRippleState,
 } from './ripple-renderer';
-import {ViewportRuler} from "../overlay/position/viewport-ruler";
+import {ViewportRuler} from '../overlay/position/viewport-ruler';
 
 
 @Directive({

src/lib/tabs/tab-nav-bar/tab-nav-bar.ts

@@ -1,7 +1,7 @@
 import {Component, Input, ViewChild, ElementRef, ViewEncapsulation, Directive} from '@angular/core';
 import {MdInkBar} from '../ink-bar';
 import {MdRipple} from '../../core/ripple/ripple';
-import {ViewportRuler} from "../../core/overlay/position/viewport-ruler";
+import {ViewportRuler} from '../../core/overlay/position/viewport-ruler';
 
 /**
  * Navigation component matching the styles of the tab group header.