Add a couple of CSS hacks in order for `scrollIntoView` to work in the "simpleviewer" component example

This is intended as a temporary solution, in order to get the "simpleviewer" example to work, until we've re-factored `scrollIntoView` to work in both the standard and components-based viewers.

examples/components/simpleviewer.html

@@ -27,6 +27,12 @@ limitations under the License.
       margin: 0;
       padding: 0;
     }
+    #viewerContainer {
+      overflow: auto;
+      position: absolute;
+      width: 100%;
+      height: 100%;
+    }
   </style>
 
   <link rel="stylesheet" href="../../build/components/pdf_viewer.css">