Encode all grit outputs in .gn files

build/config/android/rules.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/android/internal_rules.gni")
 import("//tools/grit/grit_rule.gni")
 
 assert(is_android)
 
@@ skipping 317 matching lines @@
 
 
 # Declare a target that generates localized strings.xml from a .grd file.
 #
 # If this target is included in the deps of an android resources/library/apk,
 # the strings.xml will be included with that target.
 #
 # Variables
 #   deps: Specifies the dependencies of this target.
 #   grd_file: Path to the .grd file to generate strings.xml from.
+#   outputs: Expected grit outputs (see grit rule).
 #
 # Example
 #  java_strings_grd("foo_strings_grd") {
 #    grd_file = "foo_strings.grd"
 #  }
 template("java_strings_grd") {
   base_path = "$target_gen_dir/$target_name"
   resources_zip = base_path + ".resources.zip"
 
   write_build_config("${target_name}__build_config") {
     type = "android_resources"
     if (defined(invoker.deps)) {
       deps = invoker.deps
     }
   }
 
+  # Put grit files into this subdirectory of target_gen_dir.
+  extra_output_path = target_name + "_grit_output"
+
   grit_target_name = "${target_name}__grit"
-  grit_output_dir = base_path + "_grit_output"
+  grit_output_dir = "$target_gen_dir/$extra_output_path"
   grit(grit_target_name) {
     grit_flags = [
       "-E", "ANDROID_JAVA_TAGGED_ONLY=false",
     ]
     output_dir = grit_output_dir
     resource_ids = ""
     source = invoker.grd_file
+    # The grit rule expects files relative to target_gen_dir, but this rule
+    # appends a suffix to that. This rebase will prepend extra_output_path to
+    # each filename.
+    outputs = rebase_path(invoker.outputs, ".", extra_output_path)
   }
 
   # This needs to get outputs from grit's internal target, not the final
   # source_set.
   generate_strings_outputs = get_target_outputs(":${grit_target_name}_grit")
 
   zip("${target_name}__zip") {
     base_dir = grit_output_dir
     inputs = generate_strings_outputs
     output = resources_zip
@@ skipping 65 matching lines @@
 
     if (defined(invoker.jar_excluded_patterns)) {
       jar_excluded_patterns = invoker.jar_excluded_patterns
     }
 
     if (defined(invoker.srcjar_deps)) {
       srcjar_deps = invoker.srcjar_deps
     }
   }
 }