How does Android WebView Update from Google Play work?

One of the touted features of Android 5 is the updates of WebView through Google Play. The official documents state: > The initial release for Android 5.0 includes a version of Chromium for WebView based on the Chromium M37 release... and: > Although WebView has been based on Chromium since Android 4.4, the Chromium layer is now updatable from Google Play. 1. Does it mean that the default built-in "Android Browser" is now actually Chromium M37 after updating to Android 5.0? 2. Does it mean that the default "Android Browser" auto-updates itself like the evergreen browsers on desktop? Assuming Play Store account is set up. After updating a Samsung Galaxy S4 to Android 5.0, What's My User Agent? shows that the default Internet Browser is "Chrome 34". What's going on?