By merging https://github.com/GoogleChrome/samples/pull/504, i was able to terminate connection in Chrome for Android 59.0.3056.4.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b265af93a6c5594f08c92a93a1c06cb0611c775d

commit b265af93a6c5594f08c92a93a1c06cb0611c775d
Author: avayvod <avayvod@chromium.org>
Date: Tue Apr 11 17:51:31 2017

[Cast,Android] Handle some PresentationAPI edge cases

Update MediaRouteObservers when the route is detached vs terminated.
Update MediaRouter about the route closed if there's no client record or
successful session.
All edge cases happen when the page is not using the Cast Web SDK.

BUG= 706998 
TEST=manually on https://googlechrome.github.io/samples/presentation-api/cast.html

Review-Url: https://codereview.chromium.org/2788783002
Cr-Commit-Position: refs/heads/master@{#463680}

[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/android/java/src/org/chromium/chrome/browser/media/router/ChromeMediaRouter.java
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/android/java/src/org/chromium/chrome/browser/media/router/cast/CastMediaRouteProvider.java
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/android/java/src/org/chromium/chrome/browser/media/router/cast/CreateRouteRequest.java
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/android/junit/src/org/chromium/chrome/browser/media/router/cast/CastMediaRouteProviderTest.java
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/BUILD.gn
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/android/chrome_jni_registrar.cc
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/media/android/router/media_router_android.cc
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/media/android/router/media_router_android.h
[add] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/media/android/router/media_router_android_bridge.cc
[add] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/media/android/router/media_router_android_bridge.h
[add] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/browser/media/android/router/media_router_android_unittest.cc
[modify] https://crrev.com/b265af93a6c5594f08c92a93a1c06cb0611c775d/chrome/test/BUILD.gn

Testing with Chrome Canary 59.0.3068.4 for Android after your patch

1. Go to https://googlechrome.github.io/samples/presentation-api/cast.html
2. Click on New PresentationRequest()
3. Click on presentationRequest.start()
4. Once the app starts, click on terminate().
5. Observe the app stops on the Chromecast. <--- YEAH! 
6. Click on presentationRequest.start() again.
7. Observe an empty controller dialog with DISCONNECT/STOP CASTING buttons and no title.

The commit only made it to 59.0.3069.0 (you can check at omahaproxy.appspot.com):

https://storage.googleapis.com/chromium-find-releases-static/b26.html#b265af93a6c5594f08c92a93a1c06cb0611c775d

terminate() works because the Cast app was updated so it's not tied to a Chrome release.

Argh! You're right!
It works perfectly fine in Chrome Canary 59.0.3070.4 for Android.