screen: Delay the request::wallpaper and desktop_decoration for the DPI.

With this, there is plenty of palces where the DPI can be set before
those signals are sent. This allows wallpaper with the proper DPI to
work with screens created using `fake_add`. In turn, this will allow
screen rules to control the DPI. In "the past", the DPI used for those
handler was the native DPI of the screen with no opportunity to change
it before hand.

lib/awful/screen.lua

@@ -882,6 +882,8 @@ end
 --    function(viewport --[[, args]])
 --        local geo = viewport.geometry
 --        local s = screen.fake_add(geo.x, geo.y, geo.width, geo.height)
+--        s:emit_signal("request::desktop_decoration")
+--        s:emit_signal("request::wallpaper")
 --    end
 --
 -- If you implement this by hand, you must also implement handler for the
@@ -934,9 +936,15 @@ end
 require("awful.screen.dpi")(screen, data)
 
 -- Set the wallpaper(s) and create the bar(s) for new screens
+
 capi.screen.connect_signal("added", function(s)
+    -- If it was emited from here when screens are created with fake_add,
+    -- the Lua code would not have an opportunity to polutate the screen
+    -- metadata. Thus, the DPI may be wrong when setting the wallpaper.
+    --if capi.screen.automatic_factory then
     s:emit_signal("request::desktop_decoration")
     s:emit_signal("request::wallpaper")
+    --end
 end)
 
 -- Resize the wallpaper(s)
@@ -948,15 +956,19 @@ end
 
 -- Create the bar for existing screens when an handler is added
 capi.screen.connect_signal("request::desktop_decoration::connected", function(new_handler)
-    for s in capi.screen do
-        new_handler(s)
+    if capi.screen.automatic_factory then
+        for s in capi.screen do
+            new_handler(s)
+        end
     end
 end)
 
 -- Set the wallpaper when an handler is added.
 capi.screen.connect_signal("request::wallpaper::connected", function(new_handler)
-    for s in capi.screen do
-        new_handler(s)
+    if capi.screen.automatic_factory then
+        for s in capi.screen do
+            new_handler(s)
+        end
     end
 end)
 

lib/awful/screen/dpi.lua

@@ -156,6 +156,9 @@ function module.create_screen_handler(viewport)
     )
 
     update_screen_viewport(s)
+
+    --s:emit_signal("request::desktop_decoration")
+    --s:emit_signal("request::wallpaper")
 end
 
 function module.remove_screen_handler(viewport)