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

extensions/renderer/dispatcher.cc

Index: extensions/renderer/dispatcher.cc
diff --git a/extensions/renderer/dispatcher.cc b/extensions/renderer/dispatcher.cc
index 053d688a6d4f8ca0b598ca044365fb52138a3c4c..74fe9c81c027a2e90ce5b06b9b44615521a0ea94 100644
--- a/extensions/renderer/dispatcher.cc
+++ b/extensions/renderer/dispatcher.cc
@@ -769,7 +769,6 @@ std::vector<std::pair<std::string, int> > Dispatcher::GetJsResources() {
   resources.push_back(
       std::make_pair(mojo::kValidatorModuleName, IDR_MOJO_VALIDATOR_JS));
   resources.push_back(std::make_pair("async_waiter", IDR_ASYNC_WAITER_JS));
-  resources.push_back(std::make_pair("keep_alive", IDR_KEEP_ALIVE_JS));
   resources.push_back(std::make_pair("extensions/common/mojo/keep_alive.mojom",
                                      IDR_KEEP_ALIVE_MOJOM_JS));
 
@@ -791,8 +790,6 @@ std::vector<std::pair<std::string, int> > Dispatcher::GetJsResources() {
   resources.push_back(
       std::make_pair("extension", IDR_EXTENSION_CUSTOM_BINDINGS_JS));
   resources.push_back(std::make_pair("i18n", IDR_I18N_CUSTOM_BINDINGS_JS));
-  resources.push_back(std::make_pair(
-      "mimeHandlerPrivate", IDR_MIME_HANDLER_PRIVATE_CUSTOM_BINDINGS_JS));
   resources.push_back(std::make_pair("extensions/common/api/mime_handler.mojom",
                                      IDR_MIME_HANDLER_MOJOM_JS));
   resources.push_back(