update_engine: Switch to chrome-dbus for client requests in update_engine

update_engine daemon acts as DBus client to send DBus calls to shill,
power_manager and chrome, and to listen for signals from shill, chrome
and login_manager. This patch migrates these calls and signals to use
chrome-dbus framework instead of dbus-glib.

All references to dbus-glib code are removed.

BUG=chromium:419827
TEST=Updated unittest. Deployed on a link device and tested interactions with shill and chromium.

Change-Id: I31b389e0d1690cccb115ff3b6539c876ba81bd0e
Reviewed-on: https://chromium-review.googlesource.com/290990
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
Trybot-Ready: Alex Deymo <deymo@chromium.org>
diff --git a/dbus_bindings/org.chromium.LibCrosService.xml b/dbus_bindings/org.chromium.LibCrosService.xml
new file mode 100644
index 0000000..2ea8313
--- /dev/null
+++ b/dbus_bindings/org.chromium.LibCrosService.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+
+<node name="/org/chromium/LibCrosService"
+      xmlns:tp="http://telepathy.freedesktop.org/wiki/DbusSpec#extensions-v0">
+  <interface name="org.chromium.LibCrosServiceInterface">
+    <method name="ResolveNetworkProxy">
+      <arg name="source_url" type="s" direction="in" />
+      <arg name="signal_interface" type="s" direction="in" />
+      <arg name="signal_name" type="s" direction="in" />
+      <annotation name="org.chromium.DBus.Method.Kind" value="simple" />
+    </method>
+  </interface>
+  <interface name="org.chromium.UpdateEngineLibcrosProxyResolvedInterface">
+    <signal name="ProxyResolved">
+      <arg name="source_url" type="s" direction="out" />
+      <arg name="proxy_info" type="s" direction="out" />
+      <arg name="error_message" type="s" direction="out" />
+    </signal>
+  </interface>
+</node>