GN: Put .jar files in lib.java rather than gen/

build/config/android/internal_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")
 
 assert(is_android)
 
 rebased_android_sdk = rebase_path(android_sdk, root_build_dir)
 rebased_android_sdk_root = rebase_path(android_sdk_root, root_build_dir)
@@ skipping 876 matching lines @@
 }
 
 template("java_prebuilt_impl") {
   set_sources_assignment_filter([])
   forward_variables_from(invoker, [ "testonly" ])
   _supports_android =
       defined(invoker.supports_android) && invoker.supports_android
 
   assert(defined(invoker.jar_path))
   _base_path = "${target_gen_dir}/$target_name"
-  _jar_path = _base_path + ".jar"
+
+  # Jar files can be needed at runtime (by Robolectric tests or java binaries),
+  # so do not put them under gen/.
+  target_dir_name = get_label_info(":$target_name", "dir")
+  _jar_path = "$root_out_dir/lib.java$target_dir_name/$target_name.jar"
   _build_config = _base_path + ".build_config"
 
   if (_supports_android) {
     _dex_path = _base_path + ".dex.jar"
   }
   _deps = []
   if (defined(invoker.deps)) {
     _deps = invoker.deps
   }
   _jar_deps = []
@@ skipping 240 matching lines @@
 }
 
 template("java_library_impl") {
   set_sources_assignment_filter([])
   forward_variables_from(invoker, [ "testonly" ])
 
   assert(
       defined(invoker.java_files) || defined(invoker.DEPRECATED_java_in_dir) ||
       defined(invoker.srcjars) || defined(invoker.srcjar_deps))
   _base_path = "$target_gen_dir/$target_name"
-  _jar_path = _base_path + ".jar"
+
+  # Jar files can be needed at runtime (by Robolectric tests or java binaries),
+  # so do not put them under gen/.
+  target_dir_name = get_label_info(":$target_name", "dir")
+  _jar_path = "$root_out_dir/lib.java$target_dir_name/$target_name.jar"
   if (defined(invoker.jar_path)) {
     _jar_path = invoker.jar_path
   }
   _template_name = target_name
 
   _final_deps = []
   _final_datadeps = []
   if (defined(invoker.datadeps)) {
     _final_datadeps = invoker.datadeps
   }
@@ skipping 452 matching lines @@
     ]
     args = [
       "--depfile",
       rebase_path(depfile, root_build_dir),
       "--script-output-path",
       rebase_path(generated_script, root_build_dir),
     ]
     args += test_runner_args
   }
 }