Adds lots of Mojo documentation

Adds documentation for Mojo IPC conversion and Mojo public system
libraries for C and C++. Also updates Service Manager and client
library documentation.

BUG=
[email protected],[email protected]

Review-Url: https://codereview.chromium.org/2783223004
Cr-Commit-Position: refs/heads/master@{#461306}
diff --git a/mojo/public/java/system/README.md b/mojo/public/java/system/README.md
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+# ![Mojo Graphic](https://goo.gl/6CdlbH) Mojo Java System API
+This document is a subset of the [Mojo documentation](/mojo).
+
+[TOC]
+
+## Overview
+
+This document provides a brief guide to Java Mojo bindings usage with example
+code snippets.
+
+For a detailed API references please consult the class definitions in
+[this directory](https://cs.chromium.org/chromium/src/mojo/public/java/system/src/org/chromium/mojo/system/).
+
+*TODO: Make the contents of this document less non-existent.*
+
+## Message Pipes
+
+## Data Pipes
+
+## Shared Buffers
+
+## Native Platform Handles (File Descriptors, Windows Handles, *etc.*)
+
+## Watchers
+