Componentize script to generate UI string overrides mapping.

Change the API of the script to generate both the header and source file
and to take a list of header files as input (to allow overridding strings
from components/components_strings.grd).

The script is now generating a method CreateUIStringOverrider() and hides
the arrays in the implementation file and allow customization of the
namespace in which the function and code is generated.

Introduce a new target "chrome_ui_string_overrider_factory" in the gyp
build to mimic the same target in the gn build (compiles the source file
generated by the script).

Rename the script from to generate_ui_string_overrider.py to reflect the
new role of the script and move it to components/variations/service.

Introduce .gni file to help using the script by different embedders (don't
introduce .gypi files as it is much harder to share code for gyp).

Componentize ui_string_overrider_unittest.cc.

BUG=534257

Review URL: https://codereview.chromium.org/1374773002

Cr-Commit-Position: refs/heads/master@{#352308}

16 files changed, 483 insertions, 290 deletions

diff --git a/chrome/app/BUILD.gn b/chrome/app/BUILD.gn
index 0965e6d..a5c37e7 100644
--- a/chrome/app/BUILD.gn
+++ b/chrome/app/BUILD.gn
@@ -134,38 +134,6 @@ if (is_android) {
   }
 }
 
-# GYP version: chrome/chrome_resources.gyp:chrome_strings_map
-action("make_generated_resources_map") {
-  # Targets should depend on generated_resources_map instead.
-  visibility = [ ":generated_resources_map" ]
-
-  script = "//chrome/browser/metrics/variations/generate_resources_map.py"
-
-  inputs = [
-    "$root_gen_dir/chrome/grit/generated_resources.h",
-  ]
-  outputs = [
-    "$root_gen_dir/chrome/generated_resources_map.cc",
-  ]
-
-  args =
-      rebase_path(inputs, root_build_dir) + rebase_path(outputs, root_build_dir)
-
-  deps = [
-    ":generated_resources",
-  ]
-}
-
-# Collect the generated .cc file from make_generated_resources_map and put it
-# in a source set so targets that depend on it will link the source rather than
-# specifying it manually. This doesn't happen in the GYP build.
-source_set("generated_resources_map") {
-  sources = get_target_outputs(":make_generated_resources_map")
-  deps = [
-    ":make_generated_resources_map",
-  ]
-}
-
 # GYP version: chrome/chrome_resources.gyp:chrome_strings
 #              (generate_google_chrome_strings action)
 grit("google_chrome_strings") {
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 9fa3cf0..dab46f1 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -93,9 +93,9 @@ source_set("browser") {
     "//chrome:extra_resources",
     "//chrome:resources",
     "//chrome:strings",
-    "//chrome/app:generated_resources_map",
     "//chrome/app/resources:platform_locale_settings",
     "//chrome/app/theme:theme_resources",
+    "//chrome/browser/metrics/variations:chrome_ui_string_overrider_factory",
     "//chrome/browser/net:probe_message_proto",
     "//chrome/browser/ui",
     "//chrome/common",
@@ -264,9 +264,9 @@ source_set("browser") {
     deps += [
       "//apps",
       "//cc",
-      "//chrome/app:generated_resources_map",
       "//chrome/app/theme:theme_resources",
       "//chrome/browser/devtools",
+      "//chrome/browser/metrics/variations:chrome_ui_string_overrider_factory",
       "//chrome/browser/resources:component_extension_resources",
       "//chrome/common/net",
       "//chrome/installer/util",
diff --git a/chrome/browser/metrics/metrics_services_manager.cc b/chrome/browser/metrics/metrics_services_manager.cc
index a981620..6e71aa1 100644
--- a/chrome/browser/metrics/metrics_services_manager.cc
+++ b/chrome/browser/metrics/metrics_services_manager.cc
@@ -14,7 +14,7 @@
 #include "chrome/browser/metrics/chrome_metrics_service_client.h"
 #include "chrome/browser/metrics/metrics_reporting_state.h"
 #include "chrome/browser/metrics/variations/chrome_variations_service_client.h"
-#include "chrome/browser/metrics/variations/generated_resources_map.h"
+#include "chrome/browser/metrics/variations/ui_string_overrider_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser_otr_state.h"
@@ -69,9 +69,7 @@ variations::VariationsService* MetricsServicesManager::GetVariationsService() {
     variations_service_ = variations::VariationsService::Create(
         make_scoped_ptr(new ChromeVariationsServiceClient()), local_state_,
         GetMetricsStateManager(), switches::kDisableBackgroundNetworking,
-        variations::UIStringOverrider(chrome_variations::kResourceHashes,
-                                      chrome_variations::kResourceIndices,
-                                      chrome_variations::kNumResources));
+        chrome_variations::CreateUIStringOverrider());
   }
   return variations_service_.get();
 }
diff --git a/chrome/browser/metrics/variations/BUILD.gn b/chrome/browser/metrics/variations/BUILD.gn
new file mode 100644
index 0000000..ed39b8c
--- /dev/null
+++ b/chrome/browser/metrics/variations/BUILD.gn
@@ -0,0 +1,18 @@
+# Copyright 2015 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("//components/variations/service/generate_ui_string_overrider.gni")
+
+# GYP version: chrome/chrome_resources.gyp:chrome_ui_string_overrider_factory
+generate_ui_string_overrider("chrome_ui_string_overrider_factory") {
+  inputs = [
+    "$root_gen_dir/chrome/grit/generated_resources.h",
+  ]
+  deps = [
+    "//chrome/app:generated_resources",
+  ]
+  namespace = "chrome_variations"
+  header_filename = "ui_string_overrider_factory.h"
+  source_filename = "ui_string_overrider_factory.cc"
+}
diff --git a/chrome/browser/metrics/variations/generate_resources_map.py b/chrome/browser/metrics/variations/generate_resources_map.py
deleted file mode 100755
index 6cf535b..0000000
--- a/chrome/browser/metrics/variations/generate_resources_map.py
+++ /dev/null
@@ -1,183 +0,0 @@
-#!/usr/bin/python
-# Copyright 2014 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import collections
-import hashlib
-import operator
-import os
-import re
-import sys
-
-
-RESOURCE_EXTRACT_REGEX = re.compile('^#define (\S*) (\d*)$', re.MULTILINE)
-
-class Error(Exception):
-  """Base error class for all exceptions in generated_resources_map."""
-
-
-class HashCollisionError(Error):
-  """Multiple resource names hash to the same value."""
-
-
-Resource = collections.namedtuple("Resource", ['hash', 'name', 'index'])
-
-
-def _HashName(name):
-  """Returns the hash id for a name.
-
-  Args:
-    name: The name to hash.
-
-  Returns:
-    An int that is at most 32 bits.
-  """
-  md5hash = hashlib.md5()
-  md5hash.update(name)
-  return int(md5hash.hexdigest()[:8], 16)
-
-
-def _GetNameIndexPairsIter(string_to_scan):
-  """Gets an iterator of the resource name and index pairs of the given string.
-
-  Scans the input string for lines of the form "#define NAME INDEX" and returns
-  an iterator over all matching (NAME, INDEX) pairs.
-
-  Args:
-    string_to_scan: The input string to scan.
-
-  Yields:
-    A tuple of name and index.
-  """
-  for match in RESOURCE_EXTRACT_REGEX.finditer(string_to_scan):
-    yield match.group(1, 2)
-
-
-def _GetResourceListFromString(resources_content):
-  """Produces a list of |Resource| objects from a string.
-
-  The input string conaints lines of the form "#define NAME INDEX". The returned
-  list is sorted primarily by hash, then name, and then index.
-
-  Args:
-    resources_content: The input string to process, contains lines of the form
-        "#define NAME INDEX".
-
-  Returns:
-    A sorted list of |Resource| objects.
-  """
-  resources = [Resource(_HashName(name), name, index) for name, index in
-               _GetNameIndexPairsIter(resources_content)]
-
-  # The default |Resource| order makes |resources| sorted by the hash, then
-  # name, then index.
-  resources.sort()
-
-  return resources
-
-
-def _CheckForHashCollisions(sorted_resource_list):
-  """Checks a sorted list of |Resource| objects for hash collisions.
-
-  Args:
-    sorted_resource_list: A sorted list of |Resource| objects.
-
-  Returns:
-    A set of all |Resource| objects with collisions.
-  """
-  collisions = set()
-  for i in xrange(len(sorted_resource_list) - 1):
-    resource = sorted_resource_list[i]
-    next_resource = sorted_resource_list[i+1]
-    if resource.hash == next_resource.hash:
-      collisions.add(resource)
-      collisions.add(next_resource)
-
-  return collisions
-
-
-def _GenDataArray(
-    resources, entry_pattern, array_name, array_type, data_getter):
-  """Generates a C++ statement defining a literal array containing the hashes.
-
-  Args:
-    resources: A sorted list of |Resource| objects.
-    entry_pattern: A pattern to be used to generate each entry in the array. The
-        pattern is expected to have a place for data and one for a comment, in
-        that order.
-    array_name: The name of the array being generated.
-    array_type: The type of the array being generated.
-    data_getter: A function that gets the array data from a |Resource| object.
-
-  Returns:
-    A string containing a C++ statement defining the an array.
-  """
-  lines = [entry_pattern % (data_getter(r), r.name) for r in resources]
-  pattern = """const %(type)s %(name)s[] = {
-%(content)s
-};
-"""
-  return pattern % {'type': array_type,
-                    'name': array_name,
-                    'content': '\n'.join(lines)}
-
-
-def _GenerateFileContent(resources_content):
-  """Generates the .cc content from the given generated_resources.h content.
-
-  Args:
-    resources_content: The input string to process, contains lines of the form
-        "#define NAME INDEX".
-
-  Returns:
-    .cc file content defining the kResourceHashes and kResourceIndices arrays.
-  """
-  hashed_tuples = _GetResourceListFromString(resources_content)
-
-  collisions = _CheckForHashCollisions(hashed_tuples)
-  if collisions:
-    error_message = "\n".join(
-        ["hash: %i, name: %s" % (i[0], i[1]) for i in sorted(collisions)])
-    error_message = ("\nThe following names had hash collisions "
-                     "(sorted by the hash value):\n%s\n" %(error_message))
-    raise HashCollisionError(error_message)
-
-  hashes_array = _GenDataArray(
-      hashed_tuples, "    %iU,  // %s", 'kResourceHashes', 'uint32_t',
-      operator.attrgetter('hash'))
-  indices_array = _GenDataArray(
-      hashed_tuples, "    %s,  // %s", 'kResourceIndices', 'int',
-      operator.attrgetter('index'))
-
-  return (
-      "// This file was generated by generate_resources_map.py. Do not edit.\n"
-      "\n\n"
-      "#include "
-      "\"chrome/browser/metrics/variations/generated_resources_map.h\"\n\n"
-      "namespace chrome_variations {\n\n"
-      "const size_t kNumResources = %i;\n\n"
-      "%s"
-      "\n"
-      "%s"
-      "\n"
-      "}  // namespace chrome_variations\n") % (
-          len(hashed_tuples), hashes_array, indices_array)
-
-
-def main(resources_file, map_file):
-  generated_resources_h = ""
-  with open(resources_file, "r") as resources:
-    generated_resources_h = resources.read()
-
-  if len(generated_resources_h) == 0:
-    raise Error("No content loaded for %s." % (resources_file))
-
-  file_content = _GenerateFileContent(generated_resources_h)
-
-  with open(map_file, "w") as generated_file:
-    generated_file.write(file_content)
-
-
-if __name__ == '__main__':
-  sys.exit(main(sys.argv[1], sys.argv[2]))
diff --git a/chrome/browser/metrics/variations/generated_resources_map.h b/chrome/browser/metrics/variations/generated_resources_map.h
deleted file mode 100644
index c4c6cd8..0000000
--- a/chrome/browser/metrics/variations/generated_resources_map.h
+++ /dev/null
@@ -1,35 +0,0 @@
-// 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.
-
-#ifndef CHROME_BROWSER_METRICS_VARIATIONS_GENERATED_RESOURCES_MAP_H_
-#define CHROME_BROWSER_METRICS_VARIATIONS_GENERATED_RESOURCES_MAP_H_
-
-#include "base/basictypes.h"
-
-namespace chrome_variations {
-
-// This file provides a mapping from hashes of generated resource names to their
-// IDs. This mapping is achieved by having two arrays: |kResourceHashes|, a
-// sorted array of resource name hashes; and |kResourceIndices|, an array of
-// resource indices in the same order as |kResourceHashes|. So, if
-// generated_resources.h contains |#define IDS_FOO 12345|, then for some index i
-// kResourceHashes[i] = HASH("IDS_FOO") and kResourceIndices[i] = 12345. Both
-// arrays are of length |kNumResources|.
-
-// The definitions of the arrays are generated by generate_resources_map.py from
-// the content of generated_resources.h.
-
-// Length of |kResourceHashes| and |kResourceIndices|.
-extern const size_t kNumResources;
-
-// A sorted array of hashed generated resource names.
-extern const uint32_t kResourceHashes[];
-
-// An array of generated resource indices. The order of this array corresponds
-// to the order of |kResourceHashes|.
-extern const int kResourceIndices[];
-
-}  // namespace chrome_variations
-
-#endif  // CHROME_BROWSER_METRICS_VARIATIONS_GENERATED_RESOURCES_MAP_H_
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 05d1720..1b9bd16 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1882,7 +1882,6 @@
       'browser/metrics/time_ticks_experiment_win.h',
       'browser/metrics/variations/chrome_variations_service_client.cc',
       'browser/metrics/variations/chrome_variations_service_client.h',
-      'browser/metrics/variations/generated_resources_map.h',
       'browser/metrics/variations/variations_registry_syncer_win.cc',
       'browser/metrics/variations/variations_registry_syncer_win.h',
     ],
@@ -3079,7 +3078,8 @@
         'chrome_resources.gyp:chrome_extra_resources',
         'chrome_resources.gyp:chrome_resources',
         'chrome_resources.gyp:chrome_strings',
-        'chrome_resources.gyp:chrome_strings_map',
+        'chrome_resources.gyp:chrome_ui_string_overrider_factory',
+        'chrome_resources.gyp:make_chrome_ui_string_overrider_factory',
         'chrome_resources.gyp:platform_locale_settings',
         'chrome_resources.gyp:theme_resources',
         'common',
@@ -3307,10 +3307,6 @@
             '<(grit_out_dir)/grit/component_extension_resources_map.cc',
             '<(grit_out_dir)/grit/settings_resources_map.cc',
             '<(grit_out_dir)/grit/theme_resources_map.cc',
-
-            # This file is generated by
-            # chrome/browser/metrics/variations/generate_resources_map.py
-            '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/generated_resources_map.cc',
           ],
           'conditions': [
             ['toolkit_views==1', {
diff --git a/chrome/chrome_resources.gyp b/chrome/chrome_resources.gyp
index bf21b16..041e51d 100644
--- a/chrome/chrome_resources.gyp
+++ b/chrome/chrome_resources.gyp
@@ -281,31 +281,49 @@
       ],
     },
     {
-      # GN version: //chrome/app:make_generated_resources_map
-      'target_name': 'chrome_strings_map',
+      # GN version: //chrome/browser/metrics/variations:chrome_ui_string_overrider_factory_gen_sources
+      'target_name': 'make_chrome_ui_string_overrider_factory',
       'type': 'none',
+      'hard_dependency': 1,
       'dependencies': [ 'chrome_strings', ],
       'actions': [
         {
-          'action_name': 'generate_resources_map',
+          'action_name': 'generate_ui_string_overrider',
           'inputs': [
-            'browser/metrics/variations/generate_resources_map.py',
+            '../components/variations/service/generate_ui_string_overrider.py',
             '<(grit_out_dir)/grit/generated_resources.h'
           ],
           'outputs': [
-            '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/generated_resources_map.cc',
+            '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/ui_string_overrider_factory.cc',
+            '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/ui_string_overrider_factory.h',
           ],
           'action': [
             'python',
-            'browser/metrics/variations/generate_resources_map.py',
+            '../components/variations/service/generate_ui_string_overrider.py',
+            '-N', 'chrome_variations',
+            '-o', '<(SHARED_INTERMEDIATE_DIR)',
+            '-S', 'chrome/browser/metrics/variations/ui_string_overrider_factory.cc',
+            '-H', 'chrome/browser/metrics/variations/ui_string_overrider_factory.h',
             '<(grit_out_dir)/grit/generated_resources.h',
-            '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/generated_resources_map.cc'
           ],
           'message': 'Generating generated resources map.',
         }
       ],
     },
     {
+      # GN version: //chrome/browser/metrics/variations:chrome_ui_string_overrider_factory
+      'target_name': 'chrome_ui_string_overrider_factory',
+      'type': 'static_library',
+      'dependencies': [
+        '../components/components.gyp:variations_service',
+        'make_chrome_ui_string_overrider_factory',
+      ],
+      'sources': [
+        '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/ui_string_overrider_factory.cc',
+        '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/metrics/variations/ui_string_overrider_factory.h',
+      ],
+    },
+    {
       # GN version: //chrome/app/resources:platform_locale_settings
       'target_name': 'platform_locale_settings',
       'type': 'none',
diff --git a/chrome/chrome_tests_unit.gypi b/chrome/chrome_tests_unit.gypi
index 5c08ca1..688edc5 100644
--- a/chrome/chrome_tests_unit.gypi
+++ b/chrome/chrome_tests_unit.gypi
@@ -139,7 +139,6 @@
       'browser/metrics/thread_watcher_android_unittest.cc',
       'browser/metrics/thread_watcher_unittest.cc',
       'browser/metrics/time_ticks_experiment_unittest.cc',
-      'browser/metrics/variations/ui_string_overrider_unittest.cc',
       'browser/mod_pagespeed/mod_pagespeed_metrics_unittest.cc',
       'browser/net/chrome_network_delegate_unittest.cc',
       'browser/net/dns_probe_runner_unittest.cc',
diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index d6744af..2ad674b 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -718,6 +718,7 @@
       'variations/experiment_labels_unittest.cc',
       'variations/metrics_util_unittest.cc',
       'variations/net/variations_http_header_provider_unittest.cc',
+      'variations/service/ui_string_overrider_unittest.cc',
       'variations/service/variations_service_unittest.cc',
       'variations/study_filtering_unittest.cc',
       'variations/variations_associated_data_unittest.cc',
diff --git a/components/variations/service/BUILD.gn b/components/variations/service/BUILD.gn
index 385c724..c6cf5b1 100644
--- a/components/variations/service/BUILD.gn
+++ b/components/variations/service/BUILD.gn
@@ -30,6 +30,7 @@ source_set("service") {
 source_set("unit_tests") {
   testonly = true
   sources = [
+    "ui_string_overrider_unittest.cc",
     "variations_service_unittest.cc",
   ]
 
diff --git a/components/variations/service/generate_ui_string_overrider.gni b/components/variations/service/generate_ui_string_overrider.gni
new file mode 100644
index 0000000..11de0a0
--- /dev/null
+++ b/components/variations/service/generate_ui_string_overrider.gni
@@ -0,0 +1,66 @@
+# Copyright 2015 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.
+
+# Runs the resources map generation script other the given header files to
+# produce an output file and a source_set to build it.
+#
+# Parameters:
+#   inputs:
+#     List of file name to read. Each file should be an header file generated
+#     by grit with line like "#define IDS_FOO 12345".
+#
+#   namespace (optional):
+#     Namespace in which the generated code should be scoped. If left empty,
+#     the code will be in the global namespace.
+#
+#   header_filename:
+#     Name of the generated header file.
+#
+#   source_filename:
+#     Name of the generated source file.
+#
+#   deps (optional):
+#     List of targets to depend on.
+#
+template("generate_ui_string_overrider") {
+  # Copy "target_name" to allow restrict the visibility of the generation
+  # target to that target (as ":$target_name" will have a different meaning
+  # in the "action" block).
+  source_set_target_name = target_name
+  gen_action_target_name = target_name + "_gen_sources"
+
+  action(gen_action_target_name) {
+    header_filename = "$target_gen_dir/" + invoker.header_filename
+    source_filename = "$target_gen_dir/" + invoker.source_filename
+
+    visibility = [ ":$source_set_target_name" ]
+    script = "//components/variations/service/generate_ui_string_overrider.py"
+    outputs = [
+      header_filename,
+      source_filename,
+    ]
+
+    inputs = invoker.inputs
+    if (defined(invoker.deps)) {
+      deps = invoker.deps
+    }
+
+    args = [
+             "-N" + invoker.namespace,
+             "-o" + rebase_path(root_gen_dir, root_build_dir),
+             "-H" + rebase_path(header_filename, root_gen_dir),
+             "-S" + rebase_path(source_filename, root_gen_dir),
+           ] + rebase_path(inputs, root_build_dir)
+  }
+
+  source_set(target_name) {
+    sources = get_target_outputs(":$gen_action_target_name")
+    deps = [
+      "//components/variations/service",
+      ":$gen_action_target_name",
+    ]
+
+    forward_variables_from(invoker, [ "visibility" ])
+  }
+}
diff --git a/components/variations/service/generate_ui_string_overrider.py b/components/variations/service/generate_ui_string_overrider.py
new file mode 100755
index 0000000..288272c
--- /dev/null
+++ b/components/variations/service/generate_ui_string_overrider.py
@@ -0,0 +1,292 @@
+#!/usr/bin/python
+# 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 argparse
+import collections
+import hashlib
+import operator
+import os
+import re
+import sys
+
+SCRIPT_NAME = "generate_ui_string_overrider.py"
+RESOURCE_EXTRACT_REGEX = re.compile('^#define (\S*) (\d*)$', re.MULTILINE)
+
+class Error(Exception):
+  """Base error class for all exceptions in generated_resources_map."""
+
+
+class HashCollisionError(Error):
+  """Multiple resource names hash to the same value."""
+
+
+Resource = collections.namedtuple("Resource", ['hash', 'name', 'index'])
+
+
+def _HashName(name):
+  """Returns the hash id for a name.
+
+  Args:
+    name: The name to hash.
+
+  Returns:
+    An int that is at most 32 bits.
+  """
+  md5hash = hashlib.md5()
+  md5hash.update(name)
+  return int(md5hash.hexdigest()[:8], 16)
+
+
+def _GetNameIndexPairsIter(string_to_scan):
+  """Gets an iterator of the resource name and index pairs of the given string.
+
+  Scans the input string for lines of the form "#define NAME INDEX" and returns
+  an iterator over all matching (NAME, INDEX) pairs.
+
+  Args:
+    string_to_scan: The input string to scan.
+
+  Yields:
+    A tuple of name and index.
+  """
+  for match in RESOURCE_EXTRACT_REGEX.finditer(string_to_scan):
+    yield match.group(1, 2)
+
+
+def _GetResourceListFromString(resources_content):
+  """Produces a list of |Resource| objects from a string.
+
+  The input string contains lines of the form "#define NAME INDEX". The returned
+  list is sorted primarily by hash, then name, and then index.
+
+  Args:
+    resources_content: The input string to process, contains lines of the form
+        "#define NAME INDEX".
+
+  Returns:
+    A sorted list of |Resource| objects.
+  """
+  resources = [Resource(_HashName(name), name, index) for name, index in
+               _GetNameIndexPairsIter(resources_content)]
+
+  # The default |Resource| order makes |resources| sorted by the hash, then
+  # name, then index.
+  resources.sort()
+
+  return resources
+
+
+def _CheckForHashCollisions(sorted_resource_list):
+  """Checks a sorted list of |Resource| objects for hash collisions.
+
+  Args:
+    sorted_resource_list: A sorted list of |Resource| objects.
+
+  Returns:
+    A set of all |Resource| objects with collisions.
+  """
+  collisions = set()
+  for i in xrange(len(sorted_resource_list) - 1):
+    resource = sorted_resource_list[i]
+    next_resource = sorted_resource_list[i+1]
+    if resource.hash == next_resource.hash:
+      collisions.add(resource)
+      collisions.add(next_resource)
+
+  return collisions
+
+
+def _GenDataArray(
+    resources, entry_pattern, array_name, array_type, data_getter):
+  """Generates a C++ statement defining a literal array containing the hashes.
+
+  Args:
+    resources: A sorted list of |Resource| objects.
+    entry_pattern: A pattern to be used to generate each entry in the array. The
+        pattern is expected to have a place for data and one for a comment, in
+        that order.
+    array_name: The name of the array being generated.
+    array_type: The type of the array being generated.
+    data_getter: A function that gets the array data from a |Resource| object.
+
+  Returns:
+    A string containing a C++ statement defining the an array.
+  """
+  lines = [entry_pattern % (data_getter(r), r.name) for r in resources]
+  pattern = """const %(type)s %(name)s[] = {
+%(content)s
+};
+"""
+  return pattern % {'type': array_type,
+                    'name': array_name,
+                    'content': '\n'.join(lines)}
+
+
+def _GenerateNamespacePrefixAndSuffix(namespace):
+  """Generates the namespace prefix and suffix for |namespace|.
+
+  Args:
+    namespace: A string corresponding to the namespace name. May be empty.
+
+  Returns:
+    A tuple of strings corresponding to the namespace prefix and suffix for
+    putting the code in the corresponding namespace in C++. If namespace is
+    the empty string, both returned strings are empty too.
+  """
+  if not namespace:
+    return "", ""
+  return "namespace %s {\n\n" % namespace, "\n}  // namespace %s\n" % namespace
+
+
+def _GenerateSourceFileContent(resources_content, namespace, header_filename):
+  """Generates the .cc content from the given generated grit headers content.
+
+  Args:
+    resources_content: The input string to process, contains lines of the form
+        "#define NAME INDEX".
+
+    namespace: The namespace in which the generated code should be scoped. If
+        not defined, then the code will be in the global namespace.
+
+    header_filename: Path to the corresponding .h.
+
+  Returns:
+    .cc file content implementing the CreateUIStringOverrider() factory.
+  """
+  hashed_tuples = _GetResourceListFromString(resources_content)
+
+  collisions = _CheckForHashCollisions(hashed_tuples)
+  if collisions:
+    error_message = "\n".join(
+        ["hash: %i, name: %s" % (i[0], i[1]) for i in sorted(collisions)])
+    error_message = ("\nThe following names had hash collisions "
+                     "(sorted by the hash value):\n%s\n" %(error_message))
+    raise HashCollisionError(error_message)
+
+  hashes_array = _GenDataArray(
+      hashed_tuples, "    %iU,  // %s", 'kResourceHashes', 'uint32_t',
+      operator.attrgetter('hash'))
+  indices_array = _GenDataArray(
+      hashed_tuples, "    %s,  // %s", 'kResourceIndices', 'int',
+      operator.attrgetter('index'))
+
+  namespace_prefix, namespace_suffix = _GenerateNamespacePrefixAndSuffix(
+      namespace)
+
+  return (
+      "// This file was generated by %(script_name)s. Do not edit.\n"
+      "\n"
+      "#include \"%(header_filename)s\"\n\n"
+      "%(namespace_prefix)s"
+      "namespace {\n\n"
+      "const size_t kNumResources = %(num_resources)i;\n\n"
+      "%(hashes_array)s"
+      "\n"
+      "%(indices_array)s"
+      "\n"
+      "}  // namespace\n"
+      "\n"
+      "variations::UIStringOverrider CreateUIStringOverrider() {\n"
+      "  return variations::UIStringOverrider(\n"
+      "      kResourceHashes, kResourceIndices, kNumResources);\n"
+      "}\n"
+      "%(namespace_suffix)s") % {
+          'script_name': SCRIPT_NAME,
+          'header_filename': header_filename,
+          'namespace_prefix': namespace_prefix,
+          'num_resources': len(hashed_tuples),
+          'hashes_array': hashes_array,
+          'indices_array': indices_array,
+          'namespace_suffix': namespace_suffix,
+      }
+
+
+def _GenerateHeaderFileContent(namespace, header_filename):
+  """Generates the .h for to the .cc generated by _GenerateSourceFileContent.
+
+  Args:
+    namespace: The namespace in which the generated code should be scoped. If
+        not defined, then the code will be in the global namespace.
+
+    header_filename: Path to the corresponding .h. Used to generate the include
+        guards.
+
+  Returns:
+    .cc file content implementing the CreateUIStringOverrider() factory.
+  """
+
+  include_guard = re.sub('[^A-Z]', '_', header_filename.upper()) + '_'
+  namespace_prefix, namespace_suffix = _GenerateNamespacePrefixAndSuffix(
+      namespace)
+
+  return (
+      "// This file was generated by %(script_name)s. Do not edit.\n"
+      "\n"
+      "#ifndef %(include_guard)s\n"
+      "#define %(include_guard)s\n"
+      "\n"
+      "#include \"components/variations/service/ui_string_overrider.h\"\n\n"
+      "%(namespace_prefix)s"
+      "// Returns an initialized UIStringOverrider.\n"
+      "variations::UIStringOverrider CreateUIStringOverrider();\n"
+      "%(namespace_suffix)s"
+      "\n"
+      "#endif  // %(include_guard)s\n"
+      ) % {
+          'script_name': SCRIPT_NAME,
+          'include_guard': include_guard,
+          'namespace_prefix': namespace_prefix,
+          'namespace_suffix': namespace_suffix,
+      }
+
+
+def main():
+  arg_parser = argparse.ArgumentParser(
+      description="Generate UIStringOverrider factory from resources headers "
+                  "generated by grit.")
+  arg_parser.add_argument(
+      "--output_dir", "-o", required=True,
+      help="Base directory to for generated files.")
+  arg_parser.add_argument(
+      "--source_filename", "-S", required=True,
+      help="File name of the generated source file.")
+  arg_parser.add_argument(
+      "--header_filename", "-H", required=True,
+      help="File name of the generated header file.")
+  arg_parser.add_argument(
+      "--namespace", "-N", default="",
+      help="Namespace of the generated factory function (code will be in "
+           "the global namespace if this is omitted).")
+  arg_parser.add_argument(
+      "--test_support", "-t", action="store_true", default=False,
+      help="Make internal variables accessible for testing.")
+  arg_parser.add_argument(
+      "inputs", metavar="FILENAME", nargs="+",
+      help="Path to resources header file generated by grit.")
+  arguments = arg_parser.parse_args()
+
+  generated_resources_h = ""
+  for resources_file in arguments.inputs:
+    with open(resources_file, "r") as resources:
+      generated_resources_h += resources.read()
+
+  if len(generated_resources_h) == 0:
+    raise Error("No content loaded for %s." % (resources_file))
+
+  source_file_content = _GenerateSourceFileContent(
+      generated_resources_h, arguments.namespace, arguments.header_filename)
+  header_file_content = _GenerateHeaderFileContent(
+      arguments.namespace, arguments.header_filename)
+
+  with open(os.path.join(
+      arguments.output_dir, arguments.source_filename), "w") as generated_file:
+    generated_file.write(source_file_content)
+  with open(os.path.join(
+      arguments.output_dir, arguments.header_filename), "w") as generated_file:
+    generated_file.write(header_file_content)
+
+
+if __name__ == '__main__':
+  sys.exit(main())
diff --git a/chrome/browser/metrics/variations/generate_resources_map_unittest.py b/components/variations/service/generate_ui_string_overrider_unittest.py
index a7b1a2b..55d55f3 100755
--- a/chrome/browser/metrics/variations/generate_resources_map_unittest.py
+++ b/components/variations/service/generate_ui_string_overrider_unittest.py
@@ -3,14 +3,16 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Unittests for generate_resources_map.py"""
+"""Unittests for generate_ui_string_overrider.py"""
 
 import unittest
 
-import generate_resources_map
+import generate_ui_string_overrider
 
 
 class GenerateResourcesMapUnittest(unittest.TestCase):
+  NAMESPACE = "chrome_variations"
+  OUT_HEADER = "components/variations/service/ui_string_overrider_factory.h"
   TEST_INPUT = """
 // This file is automatically generated by GRIT. Do not edit.
 
@@ -27,9 +29,10 @@ class GenerateResourcesMapUnittest(unittest.TestCase):
                        (2654138887, "IDS_BOOKMARK_BAR_IMPORT_LINK", "12501"),
                        (2894469061, "IDS_BOOKMARK_GROUP_FROM_IE", "12502"),
                        (3847176170, "IDS_BOOKMARK_GROUP_FROM_FIREFOX", "12503")]
-    expected = [generate_resources_map.Resource(*t) for t in expected_tuples]
+    expected = [
+        generate_ui_string_overrider.Resource(*t) for t in expected_tuples]
 
-    actual_tuples = generate_resources_map._GetResourceListFromString(
+    actual_tuples = generate_ui_string_overrider._GetResourceListFromString(
         self.TEST_INPUT)
 
     self.assertEqual(expected_tuples, actual_tuples)
@@ -42,31 +45,34 @@ class GenerateResourcesMapUnittest(unittest.TestCase):
                          (890, "IDS_QUX", "12503"),
                          (899, "IDS_NO", "12504"),
                          (899, "IDS_YES", "12505")]
-    list_with_collisions = [generate_resources_map.Resource(*t)
+    list_with_collisions = [generate_ui_string_overrider.Resource(*t)
                             for t in collisions_tuples]
 
     expected_collision_tuples = [(456, "IDS_BAR", "12501"),
                                  (456, "IDS_BAZ", "12502"),
                                  (899, "IDS_NO", "12504"),
                                  (899, "IDS_YES", "12505")]
-    expected_collisions = [generate_resources_map.Resource(*t)
+    expected_collisions = [generate_ui_string_overrider.Resource(*t)
                           for t in expected_collision_tuples]
 
     actual_collisions = sorted(
-        generate_resources_map._CheckForHashCollisions(list_with_collisions))
+        generate_ui_string_overrider._CheckForHashCollisions(
+            list_with_collisions))
     actual_collisions
 
     self.assertEqual(expected_collisions, actual_collisions)
 
-  def testGenerateFileContent(self):
+  def testGenerateSourceFileContent(self):
     expected = (
-        """// This file was generated by generate_resources_map.py. Do not edit.
+        """\
+// This file was generated by generate_ui_string_overrider.py. Do not edit.
 
-
-#include "chrome/browser/metrics/variations/generated_resources_map.h"
+#include "components/variations/service/ui_string_overrider_factory.h"
 
 namespace chrome_variations {
 
+namespace {
+
 const size_t kNumResources = 4;
 
 const uint32_t kResourceHashes[] = {
@@ -83,9 +89,42 @@ const int kResourceIndices[] = {
     12503,  // IDS_BOOKMARK_GROUP_FROM_FIREFOX
 };
 
+}  // namespace
+
+variations::UIStringOverrider CreateUIStringOverrider() {
+  return variations::UIStringOverrider(
+      kResourceHashes, kResourceIndices, kNumResources);
+}
+
+}  // namespace chrome_variations
+""")
+    actual = generate_ui_string_overrider._GenerateSourceFileContent(
+        self.TEST_INPUT, self.NAMESPACE, self.OUT_HEADER)
+
+    self.assertEqual(expected, actual)
+
+
+  def testGenerateHeaderFileContent(self):
+    expected = (
+        """\
+// This file was generated by generate_ui_string_overrider.py. Do not edit.
+
+#ifndef COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_FACTORY_H_
+#define COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_FACTORY_H_
+
+#include "components/variations/service/ui_string_overrider.h"
+
+namespace chrome_variations {
+
+// Returns an initialized UIStringOverrider.
+variations::UIStringOverrider CreateUIStringOverrider();
+
 }  // namespace chrome_variations
+
+#endif  // COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_FACTORY_H_
 """)
-    actual = generate_resources_map._GenerateFileContent(self.TEST_INPUT)
+    actual = generate_ui_string_overrider._GenerateHeaderFileContent(
+        self.NAMESPACE, self.OUT_HEADER)
 
     self.assertEqual(expected, actual)
 
diff --git a/components/variations/service/ui_string_overrider.h b/components/variations/service/ui_string_overrider.h
index 5908444..8aa4784 100644
--- a/components/variations/service/ui_string_overrider.h
+++ b/components/variations/service/ui_string_overrider.h
@@ -16,7 +16,7 @@ namespace variations {
 // array of resource name hashes, and |resource_indices| an array of resource
 // indices in the same order.
 //
-// The mapping is created by generate_resources_map.py based on generated
+// The mapping is created by generate_ui_string_overrider.py based on generated
 // resources header files. The script ensure that if one header file contains
 // |#define IDS_FOO 12345| then for some index |i|, |resource_hashes[i]| will
 // be equal to |HASH("IDS_FOO")| and |resource_indices[i]| will be equal to
diff --git a/chrome/browser/metrics/variations/ui_string_overrider_unittest.cc b/components/variations/service/ui_string_overrider_unittest.cc
index 5aace0e..640d51c 100644
--- a/chrome/browser/metrics/variations/ui_string_overrider_unittest.cc
+++ b/components/variations/service/ui_string_overrider_unittest.cc
@@ -4,15 +4,30 @@
 
 #include "components/variations/service/ui_string_overrider.h"
 
-#include "chrome/browser/metrics/variations/generated_resources_map.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-// TODO(sdefresne): componentize this tests as part of the resolution
-// of http://crbug.com/534257 ("Decouple iOS port from using //chrome's
-// VariationsService client").
-
 namespace chrome_variations {
 
+namespace {
+
+const size_t kNumResources = 4;
+
+const uint32_t kResourceHashes[] = {
+    301430091U,  // IDS_BOOKMARKS_NO_ITEMS
+    2654138887U,  // IDS_BOOKMARK_BAR_IMPORT_LINK
+    2894469061U,  // IDS_BOOKMARK_GROUP_FROM_IE
+    3847176170U,  // IDS_BOOKMARK_GROUP_FROM_FIREFOX
+};
+
+const int kResourceIndices[] = {
+    12500,  // IDS_BOOKMARKS_NO_ITEMS
+    12501,  // IDS_BOOKMARK_BAR_IMPORT_LINK
+    12502,  // IDS_BOOKMARK_GROUP_FROM_IE
+    12503,  // IDS_BOOKMARK_GROUP_FROM_FIREFOX
+};
+
+}  // namespace
+
 class UIStringOverriderTest : public ::testing::Test {
  public:
   UIStringOverriderTest()
@@ -33,8 +48,8 @@ TEST_F(UIStringOverriderTest, LookupNotFound) {
   EXPECT_EQ(-1, GetResourceIndex(kResourceHashes[kNumResources - 1] + 1));
 
   // Lookup a hash that shouldn't exist.
-  // 13257681U is 1 + the hash for IDS_ZOOM_NORMAL
-  EXPECT_EQ(-1, GetResourceIndex(13257681U));
+  // 3847176171U is 1 + the hash for IDS_BOOKMARK_GROUP_FROM_FIREFOX.
+  EXPECT_EQ(-1, GetResourceIndex(3847176171U));
 }
 
 TEST_F(UIStringOverriderTest, LookupFound) {