monitor-manager: Make scale floats in D-Bus API

We don't want to limit ourself to whole integers for configuration, as
that'd mean it wouldn't be able to provide configurations for
fractional scalings. Thus, change scales to be referred to as floats
instead of ints.

https://bugzilla.gnome.org/show_bug.cgi?id=777732

src/backends/meta-monitor-manager.c

@@ -1177,14 +1177,14 @@ meta_monitor_manager_legacy_handle_apply_configuration  (MetaDBusDisplayConfig *
 #define META_DISPLAY_CONFIG_MODE_FLAGS_PREFERRED (1 << 0)
 #define META_DISPLAY_CONFIG_MODE_FLAGS_CURRENT (1 << 1)
 
-#define MODE_FORMAT "(iidiu)"
+#define MODE_FORMAT "(iiddu)"
 #define MODES_FORMAT "a" MODE_FORMAT
 #define MONITOR_SPEC_FORMAT "(ssss)"
 #define MONITOR_FORMAT "(" MONITOR_SPEC_FORMAT MODES_FORMAT "a{sv})"
 #define MONITORS_FORMAT "a" MONITOR_FORMAT
 
 #define LOGICAL_MONITOR_MONITORS_FORMAT "a" MONITOR_SPEC_FORMAT
-#define LOGICAL_MONITOR_FORMAT "(iiii" LOGICAL_MONITOR_MONITORS_FORMAT "iba{sv})"
+#define LOGICAL_MONITOR_FORMAT "(iiii" LOGICAL_MONITOR_MONITORS_FORMAT "dba{sv})"
 #define LOGICAL_MONITORS_FORMAT "a" LOGICAL_MONITOR_FORMAT
 
 static gboolean
@@ -1237,7 +1237,7 @@ meta_monitor_manager_handle_get_current_state (MetaDBusDisplayConfig *skeleton,
                                  monitor_mode_spec->width,
                                  monitor_mode_spec->height,
                                  monitor_mode_spec->refresh_rate,
-                                 preferred_scale,
+                                 (double) preferred_scale,
                                  flags);
         }
 
@@ -1289,7 +1289,7 @@ meta_monitor_manager_handle_get_current_state (MetaDBusDisplayConfig *skeleton,
                              logical_monitor->rect.width,
                              logical_monitor->rect.height,
                              &logical_monitor_monitors_builder,
-                             logical_monitor->scale,
+                             (double) logical_monitor->scale,
                              logical_monitor->is_primary,
                              NULL);
     }

src/org.gnome.Mutter.DisplayConfig.xml

@@ -308,7 +308,7 @@
 	    * i width: width in physical pixels
 	    * i height: height in physical pixels
 	    * d refresh rate: refresh rate
-	    * i preferred scale: scale preferred as per calculations
+	    * d preferred scale: scale preferred as per calculations
 	    * u flags: mode flags (see below)
 	* a{sv} properties: optional properties, including:
 	    - "width_mm" (i): physical width of monitor in millimeters
@@ -333,7 +333,7 @@
 	    * vendor: vendor name
 	    * product: product name
 	    * serial: product serial
-	* i scale: scale
+	* d scale: scale
 	* b primary: true if this is the primary logical monitor
 	* a{sv} properties: possibly other properties
 
@@ -343,8 +343,8 @@
     -->
     <method name="GetCurrentState">
       <arg name="serial" direction="out" type="u" />
-      <arg name="monitors" direction="out" type="a((ssss)a(iidiu)a{sv})" />
+      <arg name="monitors" direction="out" type="a((ssss)a(iiddu)a{sv})" />
-      <arg name="logical_monitors" direction="out" type="a(iiiia(ssss)iba{sv})" />
+      <arg name="logical_monitors" direction="out" type="a(iiiia(ssss)dba{sv})" />
       <arg name="max_screen_size" direction="out" type="(ii)" />
     </method>
   </interface>