docs(protractor): add protractor support documentation (#174)

closes #169

Author: cnishina

README.md

@@ -1,5 +1,5 @@
 
-Webdriver Manager [![Build Status](https://travis-ci.org/angular/webdriver-manager.png?branch=master)](https://travis-ci.org/angular/webdriver-manager) [![Join the chat at https://gitter.im/angular/webdriver-manager](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/angular/webdriver-manager?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+Webdriver Manager [![Build Status](https://travis-ci.org/angular/webdriver-manager.svg?branch=master)](https://travis-ci.org/angular/webdriver-manager) [![Join the chat at https://gitter.im/angular/webdriver-manager](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/angular/webdriver-manager?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 =================
 
 A selenium server and browser driver manager for your end to end tests. This is the same tool as `webdriver-manager` from the [Protractor](https://github.com/angular/protractor) repository.
@@ -47,7 +47,8 @@ Clear out the server and driver files. If `webdriver-manager start` does not wor
 webdriver-manager clean
 ```
 
-Mobile Support
+Other topics:
 --------------
 
-See [`mobile.md`](mobile.md).
+- [mobile browser support](docs/mobile.md)
+- [protractor support](docs/protractor.md)

browsers.md

@@ -0,0 +1,5 @@
+# Contents
+
+- [main page](../README.md)
+- [mobile browser support](mobile.md)
+- [protractor support](protractor.md)

docs/README.md

@@ -0,0 +1,41 @@
+# Protractor support topics
+
+## Supported browsers
+
+### Tests with Protractor test suite (v 4.0.13)
+
+The following are the supported browsers / drivers based on running the
+Protractor test suite. Since the test suite checks only firefox and chrome,
+these are the only browsers reported.
+
+### Current supported browsers / drivers
+
+| selenium standalone | firefox | chromedriver | chrome |
+| ------------------- | ------- | ------------ | ------ |
+| 2.53.1              | 47.0.1  | 2.26         | 54     |
+
+
+### Investigated
+
+| selenium standalone | firefox 47.0.1 | firefox 49.0.1 |
+| ------------------- | -------------- | -------------- |
+| 2.53.1              | pass           | fail           |
+| 3.0.0               | fail           | fail           |
+
+
+## Driver providers
+
+There are a couple cases where Protractor launches downloaded binaries
+(from webdriver-manager) without specifying which version to use:
+
+- local driver providers - when no `seleniumAddress`, `directConnect`, saucelabs
+  or browser stack configuration is set
+- direct connect - when setting `directConnect` to true
+
+Protractor knows which downloaded binaries to use based on the
+`update-config.json`. The `update-config.json` is written during the `update`
+command and provides the path to the current downloaded version and a list of
+all the binaries previously downloaded.
+
+During the launch of either local driver provider or direct connect, Protractor
+will launch the last downloaded binary.