It turns out that we also need to update the way we request permission to access contacts for O:
https://developer.android.com/preview/behavior-changes.html

Details are listed in this section:
Account access and discoverability

I built our internal remoting_google_apk with target_sdk changed to 26 with internal test signing keys, and it worked fine on a device with dev_keys build of Android O - I was able to see the device's accounts and connect to a remote machine from there.

So the problem only affects open-source builds from the public repository. We do want to get the open-source account switcher working with O (as it prevents us using development builds). But for now, I think we can go ahead and update the manifest to target O.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d7d9e946cef9ec23de8ac9496c80f3d831142e81

commit d7d9e946cef9ec23de8ac9496c80f3d831142e81
Author: joedow <joedow@chromium.org>
Date: Mon Jul 10 17:12:35 2017

Updating CRD app manifest to target API level 26

BUG= 704216 

Review-Url: https://codereview.chromium.org/2936673003
Cr-Commit-Position: refs/heads/master@{#485301}

[modify] https://crrev.com/d7d9e946cef9ec23de8ac9496c80f3d831142e81/remoting/android/java/AndroidManifest.xml.jinja2

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/651e99db59fb3300f99abdd2bd5651f46dbb4163

commit 651e99db59fb3300f99abdd2bd5651f46dbb4163
Author: Lambros Lambrou <lambroslambrou@chromium.org>
Date: Wed Jul 12 04:05:01 2017

[remoting android] Implement AccountSwitcherBasic for Android O

Android O introduces a new authentication model for accessing the list
of accounts on the device. Each account has to be specifically
authorized for the app before it will appear in the list returned by
the system's AccountsManager.

This CL rewrites the open-source account-switcher so it will work on
Android O devices, now that the app's AndroidManifest has been updated
to target Android O.

Bug:  704216 
Change-Id: I35497209114d10a818424d04ca3215cca68c386d
Reviewed-on: https://chromium-review.googlesource.com/566989
Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Lambros Lambrou <lambroslambrou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485826}
[modify] https://crrev.com/651e99db59fb3300f99abdd2bd5651f46dbb4163/remoting/android/client_java_tmpl.gni
[delete] https://crrev.com/834ed117a4b677e9868556b8d7ad8d2aeb622413/remoting/android/java/res/layout/account_dropdown.xml
[add] https://crrev.com/651e99db59fb3300f99abdd2bd5651f46dbb4163/remoting/android/java/res/layout/account_ui.xml
[delete] https://crrev.com/834ed117a4b677e9868556b8d7ad8d2aeb622413/remoting/android/java/src/org/chromium/chromoting/AccountsAdapter.java
[add] https://crrev.com/651e99db59fb3300f99abdd2bd5651f46dbb4163/remoting/android/java/src/org/chromium/chromoting/accountswitcher/AccountManagerCompat.java
[modify] https://crrev.com/651e99db59fb3300f99abdd2bd5651f46dbb4163/remoting/android/java/src/org/chromium/chromoting/accountswitcher/AccountSwitcherBasic.java
[modify] https://crrev.com/651e99db59fb3300f99abdd2bd5651f46dbb4163/remoting/resources/remoting_strings.grd