Add the shell introspection interface

Forgotten file -> broken build :(

data/Makefile.am.inc

@@ -40,6 +40,7 @@ EXTRA_DIST += \
         data/org.gnome.Mutter.ScreenCast.xml    \
         data/org.gnome.Mutter.RemoteDesktop.xml \
         data/org.gnome.SessionManager.xml       \
+        data/org.gnome.Shell.Introspect.xml     \
         data/org.gnome.Shell.Screenshot.xml     \
         data/org.gnome.ScreenSaver.xml          \
         data/org.freedesktop.ScreenSaver.xml    \

data/org.gnome.Shell.Introspect.xml

@@ -0,0 +1,61 @@
+<!DOCTYPE node PUBLIC
+'-//freedesktop//DTD D-BUS Object Introspection 1.0//EN'
+'http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd'>
+<node>
+
+  <!--
+      org.gnome.Shell.Introspect:
+      @short_description: Introspection interface
+
+      The interface used to introspect the state of Shell, such as running
+      applications, currently active application, etc.
+  -->
+  <interface name="org.gnome.Shell.Introspect">
+
+    <!--
+        RunningApplicationsChanged:
+        @short_description: Notifies when the running applications changes
+    -->
+    <signal name="RunningApplicationsChanged" />
+
+    <!--
+        GetRunningApplications:
+        @short_description: Retrieves the description of all running applications
+
+        Each application is associated by an application ID. The details of
+        each application consists of a varlist of keys and values. Available
+        keys are listed below.
+
+        'active-on-seats' - (as)   list of seats the application is active on
+                                   (a seat only has at most one active
+                                   application)
+    -->
+    <method name="GetRunningApplications">
+      <arg name="apps" direction="out" type="a{sa{sv}}" />
+    </method>
+
+    <!--
+        GetWindows:
+        @short_description: Retrieves the current list of windows and their properties
+
+        A window is exposed as:
+        * t ID: unique ID of the window
+        * a{sv} properties: high-level properties
+
+          Known properties:
+
+          - "title"       (s): (readonly) title of the window
+          - "app-id"      (s): (readonly) application ID of the window
+          - "wm-class"    (s): (readonly) class of the window
+          - "client-type" (u): (readonly) 0 for Wayland, 1 for X11
+          - "is-hidden"   (b): (readonly) if the window is currently hidden
+          - "has-focus"   (b): (readonly) if the window currently have
+                                          keyboard focus
+          - "width"       (u): (readonly) width of the window
+          - "height"      (u): (readonly) height of the window
+    -->
+    <method name="GetWindows">
+      <arg name="windows" direction="out" type="a{ta{sv}}" />
+    </method>
+  </interface>
+</node>