Add build dependency from the grit template to base

Code generated by grit depends on //base (base/stl_util.h)
so the build target will need to depend on //base as well.

Found when gn check was taught to look at generated files and not
just at files in the source tree.

Bug: 938933
Change-Id: I566d8c1f0c6b8d16ec21eb7cc864f86b4ed08370
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1505943
Commit-Queue: Daniel Bratell <bratell@opera.com>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Daniel Bratell <bratell@opera.com>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638191}

tools/grit/grit_rule.gni

@@ -467,6 +467,10 @@ template("grit") {
       ":$grit_custom_target",
     ]
 
+    deps = [
+      "//base",
+    ]
+
     if (defined(invoker.public_configs)) {
       public_configs += invoker.public_configs
     }