Fixes gn-check errors with enable_plugins=false.

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 43cf6e0be8e2e76bb0c9e3e946daad17c98f9b2b..702f3d1d473a3f35dbfc730954e51535184ec09e 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -3064,8 +3064,6 @@ split_static_library("browser") {
       "chrome_browser_main_posix.h",
       "chrome_process_singleton.cc",
       "chrome_process_singleton.h",
-      "component_updater/widevine_cdm_component_installer.cc",
-      "component_updater/widevine_cdm_component_installer.h",
       "custom_handlers/register_protocol_handler_permission_request.cc",
       "custom_handlers/register_protocol_handler_permission_request.h",
       "custom_home_pages_table_model.cc",
@@ -3455,6 +3453,13 @@ split_static_library("browser") {
     ]
   }
 
+  if (enable_pepper_cdms) {
+    sources += [
+      "component_updater/widevine_cdm_component_installer.cc",
+      "component_updater/widevine_cdm_component_installer.h",
+    ]
+  }
+
   if (!is_chrome_branded) {
     sources += [
       "search/local_files_ntp_source.cc",