Ozone: Remove the caca platform from the tree

ui/ozone/ozone.gni

Index: ui/ozone/ozone.gni
diff --git a/ui/ozone/ozone.gni b/ui/ozone/ozone.gni
index 629b75f9bb9cfae10b2960d66520bc34999e53a9..f6493c2d81f1d07c1d2f7fcb26037db0f05776ff 100644
--- a/ui/ozone/ozone.gni
+++ b/ui/ozone/ozone.gni
@@ -22,7 +22,6 @@ declare_args() {
   ozone_platform = ""
 
   # Enable individual platforms.
-  ozone_platform_caca = false
   ozone_platform_cast = false
   ozone_platform_gbm = false
   ozone_platform_headless = false
@@ -59,7 +58,7 @@ declare_args() {
   }
 }
 
-assert(use_ozone || !(ozone_platform_caca || ozone_platform_cast ||
-                          ozone_platform_gbm || ozone_platform_headless ||
-                          ozone_platform_x11 || ozone_platform_wayland),
+assert(use_ozone || !(ozone_platform_cast || ozone_platform_gbm ||
+                          ozone_platform_headless || ozone_platform_x11 ||
+                          ozone_platform_wayland),
        "Must set use_ozone to select ozone platforms")