Add CC dark theme option

This commit adds an option to enable a dark theme in the Community
Console. It can be enabled manually with a switch which is injected in
the CC or automatically by syncing it with the OS dark mode setting.

Change-Id: I7506e80a409c5b0190d942c9de88354b6c0cce10
diff --git a/templates/manifest.gjson b/templates/manifest.gjson
index 5fd7fff..5905d74 100644
--- a/templates/manifest.gjson
+++ b/templates/manifest.gjson
@@ -17,7 +17,7 @@
     },
     {
       "matches": ["https://support.google.com/s/community*"],
-      "js": ["content_scripts/console_inject_start.js"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject_start.js"],
       "run_at": "document_start"
     },
     {
@@ -48,7 +48,9 @@
   ],
   "web_accessible_resources": [
     "injections/profileindicator_inject.js",
-    "injections/profileindicator_inject.css"
+    "injections/profileindicator_inject.css",
+    "injections/ccdarktheme.css",
+    "injections/ccdarktheme_switch.css"
   ],
   "browser_action": {},
 #if defined(CHROMIUM)