Fix imports in gcc_toolchain.gni to not rely on //tools.

build/config/android/config.gni

Index: build/config/android/config.gni
diff --git a/build/config/android/config.gni b/build/config/android/config.gni
index 75ab921e2720c5f4b54d3bb590da4dc6efb61754..b658069a34895f6c3b316f17c5c268c0cb44fa29 100644
--- a/build/config/android/config.gni
+++ b/build/config/android/config.gni
@@ -323,3 +323,9 @@ if (is_android) {
     }
   }
 }
+
+declare_args() {
+  # Enables used resource whitelist generation. Set for official builds only
+  # as a large amount of build output is generated.
+  enable_resource_whitelist_generation = is_android && is_official_build
+}