classic: Replace mini-extensions with mode-specific overridesSchema

Some default values differ between classic and normal sessions. We
used to implement this by overriding the shell's default values in
mini-extensions (or more precisely: reversing the shell's overrides).
Use a mode-specific overridesSchema instead, which has the advantage
that settings defaults will not change unexpectedly when extensions
are disabled/enabled (for instance during screen locks).

https://bugzilla.gnome.org/show_bug.cgi?id=701717

data/Makefile.am

@@ -28,6 +28,12 @@ theme_DATA = 				\
 	$(srcdir)/gnome-classic.css		\
 	$(NULL)
 
+gsettings_in_files = org.gnome.shell.extensions.classic-overrides.gschema.xml.in
+gsettings_SCHEMAS = $(gsettings_in_files:.xml.in=.xml)
+
+@INTLTOOL_XML_NOMERGE_RULE@
+@GSETTINGS_RULES@
+
 %.desktop.in:%.desktop.in.in
 	$(AM_V_GEN) sed \
 		-e "s|\@libexecdir\@|$(libexecdir)|" \
@@ -54,6 +60,7 @@ EXTRA_DIST = \
 	$(session_in_in_files) \
 	$(xsession_in_files) \
 	$(mode_in_files) \
+	$(gsettings_in_files) \
 	$(theme_DATA) \
 	$(NULL)
 
@@ -62,4 +69,5 @@ CLEANFILES = \
 	$(session_DATA) \
 	$(xsession_DATA) \
 	$(mode_DATA) \
+	$(gsettings_SCHEMAS) \
 	$(NULL)

data/classic.json.in

@@ -1,6 +1,7 @@
 {
     "parentMode": "user",
     "stylesheetName": "gnome-classic.css",
+    "overridesSchema": "org.gnome.shell.extensions.classic-overrides",
     "enabledExtensions": [@CLASSIC_EXTENSIONS@],
     "panel": { "left": ["activities", "appMenu"],
                "center": [],

data/org.gnome.shell.extensions.classic-overrides.gschema.xml.in

@@ -0,0 +1,38 @@
+<schemalist>
+  <schema id="org.gnome.shell.extensions.classic-overrides"
+          path="/org/gnome/shell/extensions/classic-overrides/"
+	  gettext-domain="gnome-shell-extensions">
+    <key name="attach-modal-dialogs" type="b">
+      <default>true</default>
+      <_summary>Attach modal dialog to the parent window</_summary>
+      <_description>
+        This key overrides the key in org.gnome.mutter when running
+        GNOME Shell.
+      </_description>
+    </key>
+
+    <key name="edge-tiling" type="b">
+      <default>true</default>
+      <_summary>Enable edge tiling when dropping windows on screen edges</_summary>
+      <_description>
+        This key overrides the key in org.gnome.mutter when running GNOME Shell.
+      </_description>
+    </key>
+
+    <key name="workspaces-only-on-primary" type="b">
+      <default>true</default>
+      <_summary>Workspaces only on primary monitor</_summary>
+      <_description>
+        This key overrides the key in org.gnome.mutter when running GNOME Shell.
+      </_description>
+    </key>
+
+    <key name="focus-change-on-pointer-rest" type="b">
+      <default>true</default>
+      <summary>Delay focus changes in mouse mode until the pointer stops moving</summary>
+      <description>
+        This key overrides the key in org.gnome.mutter when running GNOME Shell.
+      </description>
+    </key>
+  </schema>
+</schemalist>