gtk: Improve menu appearance.

resources/gtkrc

 gtk_color_scheme = "fg_color:#000\nbg_color:#F7F7F7\nbase_color:#F7F7F7\ntext_color:#000\nselected_bg_color:#000\nselected_fg_color:#000\ntooltip_bg_color:#F7F7F7\ntooltip_fg_color:#000\n"
 
 gtk-font-name="ChromeDroidSans 9"
 
-# Disable button images.
+# Disable menu and button icons.
+gtk-menu-images = 0
 gtk-button-images = 0
 
 # Diable mnemonics for labels and menu items.
 gtk-enable-mnemonics = 0
 
 # Disable the "Input Methods" sub menu in context menus.
 gtk-show-input-method-menu = 0
 
 # Disable the "Insert Unicode Control Character" sub menu in context menus.
 gtk-show-unicode-menu = 0
@@ skipping 57 matching lines @@
   # Tweak the width of scrollbars slightly. This results in an overall width of
   # 15 vs 16 stock.
   GtkScrollbar::slider-width = 13
 
   # Give more padding to buttons (default is 1, 1, 1, 1).
   GtkButton::inner-border = { 5, 5, 1, 1 }
 
   # Turn off extra menu vertical padding
   GtkMenu::vertical-padding = 0
 
+  # Cut down horizontal padding on menu items since we're not using icons.
+  GtkMenuItem::horizontal-padding = 0
+  GtkMenuItem::toggle-spacing = 0
+
   engine "theme" { }
 }
 
 style "NotebookStyle" = "default" {
   # How much tabs shift when selected is dictated by the xthickness. Ideally we
   # would set this to 0 as we don't want a shift, but this is also used for the
   # padding around the children of the tab, so that if we set the thickenss to
   # 0 there is no padding around the children of the tab and they draw over the
   # border.
   xthickness = 1
@@ skipping 49 matching lines @@
 widget "*.chromeos-options-tab" style "WhiteBackgroundStyle"
 
 widget "*.chromeos-options-tab*.GtkEventBox" style "WhiteBackgroundStyle"
 
 # GTK+ hardcodes Ctrl-/ to select all text, just like Ctrl-A.  Unbind it
 # here so we can bind it ourselves to do something else in Chrome.
 binding "UnbindControlSlash" {
   unbind "<Control>slash"
 }
 class "*" binding "UnbindControlSlash"