=== Multi-process and IPC ===
To [[File:WebNavigationE10S.png|left|thumb|500px|<xul:remote-browser>, frameloader and docshell in multiprocess configuration. The horizontal dash-lines represent inter-process communication]] In a multi-process desktop Firefox, a tab is managed by <code>[https://dxr.mozilla.org/mozilla-central/source/toolkit/content/widgets/remote-browser.xml <xul:remote-browser>]</code>. It still operates on nsIWebNavigation, but in this case the docshell is in a remote process and can not be writtenaccessed directly. The encapsulation of remote nsIWebNavigation is done by the javascript-implemented <code>[https://dxr.mozilla.org/mozilla-central/source/toolkit/components/remotebrowserutils/RemoteWebNavigation.js RemoteWebNavigation]</code>. In this configuration, the frameloader of a root docshell lives in parent process, so it can not access docshell directly either. Instead, it holds a <code>[https://dxr.mozilla.org/mozilla-central/source/dom/ipc/TabParent.h TabParent]</code> instance to interact with <code>[https://dxr.mozilla.org/mozilla-central/source/dom/ipc/TabChild.h TabChild]</code> in child-process. At C/C++ level, the communication across processes for a single tab is through the '''PBrowser''' IPC protocol implemented by TabParent and TabChild, while at the javascript level it's done by '''message manager''' (which is ontop of PBrowser).
== Networking ==
