Speculative fix for com.google.android.apps.chrome.uiautomator.WebContentsTest#testClickingOnLink

LinkHighlight depends on compositor information, so it should make
sure that it's up to date first. WebViewImpl::layout updates
layout and compositing state.

BUG=343652

Review URL: https://codereview.chromium.org/165263005

git-svn-id: svn://svn.chromium.org/blink/trunk@167527 bbb929c8-8fbe-4397-9dbb-9b2b20218538