fix(searchbar): set a negative tabindex for the cancel button

this prevents tabbing to the cancel button and shifting the entire
screen.

Author: brandyscarney

src/components/searchbar/searchbar.ts

@@ -41,7 +41,7 @@ import {isPresent} from '../../util/util';
       '<input #searchbarInput [(ngModel)]="_value" [attr.placeholder]="placeholder" (input)="inputChanged($event)" (blur)="inputBlurred($event)" (focus)="inputFocused($event)" class="searchbar-input">' +
       '<button clear class="searchbar-clear-icon" (click)="clearInput($event)" (mousedown)="clearInput($event)"></button>' +
     '</div>' +
-    '<button #cancelButton clear (click)="cancelSearchbar($event)" (mousedown)="cancelSearchbar($event)" [hidden]="hideCancelButton" class="searchbar-ios-cancel">{{cancelButtonText}}</button>',
+    '<button #cancelButton [tabindex]="_isActive ? 1 : -1" clear (click)="cancelSearchbar($event)" (mousedown)="cancelSearchbar($event)" [hidden]="hideCancelButton" class="searchbar-ios-cancel">{{cancelButtonText}}</button>',
   encapsulation: ViewEncapsulation.None
 })
 export class Searchbar {