Use mojo from the PDF extension instead of using an extension API.

extensions/renderer/resources/extensions_renderer_resources.grd

Index: extensions/renderer/resources/extensions_renderer_resources.grd
diff --git a/extensions/renderer/resources/extensions_renderer_resources.grd b/extensions/renderer/resources/extensions_renderer_resources.grd
index 2e4502ad2fd4adba1708451509466cd6a758eed1..e8502a5d594c04bf92e58d1d9c20a8c3b648e2b8 100644
--- a/extensions/renderer/resources/extensions_renderer_resources.grd
+++ b/extensions/renderer/resources/extensions_renderer_resources.grd
@@ -33,12 +33,10 @@
       <include name="IDR_GUEST_VIEW_JS" file="guest_view/guest_view.js" type="BINDATA" />
       <include name="IDR_IMAGE_UTIL_JS" file="image_util.js" type="BINDATA" />
       <include name="IDR_JSON_SCHEMA_JS" file="json_schema.js" type="BINDATA" />
-      <include name="IDR_KEEP_ALIVE_JS" file="keep_alive.js" type="BINDATA" />
       <include name="IDR_KEEP_ALIVE_MOJOM_JS" file="${mojom_root}\extensions\common\mojo\keep_alive.mojom.js" use_base_dir="false" type="BINDATA" />
       <include name="IDR_LAST_ERROR_JS" file="last_error.js" type="BINDATA" />
       <include name="IDR_MESSAGING_JS" file="messaging.js" type="BINDATA" />
       <include name="IDR_MESSAGING_UTILS_JS" file="messaging_utils.js" type="BINDATA" />
-      <include name="IDR_MIME_HANDLER_PRIVATE_CUSTOM_BINDINGS_JS" file="mime_handler_private_custom_bindings.js" type="BINDATA" />
       <include name="IDR_MIME_HANDLER_MOJOM_JS" file="${mojom_root}\extensions\common\api\mime_handler.mojom.js" use_base_dir="false" type="BINDATA" />
       <include name="IDR_SCHEMA_UTILS_JS" file="schema_utils.js" type="BINDATA" />
       <include name="IDR_SEND_REQUEST_JS" file="send_request.js" type="BINDATA" />