bluetooth: Enable Web Bluetooth on experimental framework

This enables Web Bluetooth through experimental frameworks in supported platforms.
Intent to Experiment: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/coyvHj1u2Z8

Adds the OriginTrialEnabled extended binding so that the bindings are visible
to domains that have valid EF tokens.

Also adds WebBluetooth to frames and BluetoothDispatcherHost to processes' filters for supported platforms.

TEST=Manual testing required:
Launch chrome and perform the following tests:

On a Chrome OS device and an Android device:
1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth Works".

1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/not-allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth Unavailable".

On a Linux, OSX and Windows devices:
1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth blocked".

1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/not-allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth Unavailable".

Launch Chrome with the following command line flag: --enable-web-bluetooth

On a Chrome OS, Android, Linux, OSX, and Windows devices:
1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth Works".

On a Chrome OS, Android, Linux, OSX, and Windows devices:
1. Visit: https://g-ortuno.github.io/web-bluetooth-sandbox/not-allowed.html
2. Press the "Run Test" button.
3. "Web Bluetooth bindings" should be "Present" and "Use Web Bluetooth" should
   be "Bluetooth Works".

BUG=584113
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_site_isolation

Review URL: https://codereview.chromium.org/1858293002

Cr-Commit-Position: refs/heads/master@{#385814}
15 files changed