Allow embedders to share code to override UI strings.

components/variations/service/ui_string_overrider.h

Index: components/variations/service/ui_string_overrider.h
diff --git a/components/variations/service/ui_string_overrider.h b/components/variations/service/ui_string_overrider.h
new file mode 100644
index 0000000000000000000000000000000000000000..f1d3f7b539dba25dc430b9378e40ae7231976576
--- /dev/null
+++ b/components/variations/service/ui_string_overrider.h
@@ -0,0 +1,51 @@
+// 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.
+
+#ifndef COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_H_
+#define COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_H_
+
+#include "base/basictypes.h"
+#include "base/strings/string16.h"
+
+namespace variations {
+
+// Provides a mapping from hashes of generated reosurce names to their IDs. The
+// mapping is provided by the embedder as two arrays |resource_hashes|, a sorted
+// 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
+// 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
+// |12345|.
+//
+// Both array must have the same length |num_resources|. They are not owned by
+// the UIStringOverrider and the embedder is responsible for their lifetime
+// (usually by passing pointer to static data).
+class UIStringOverrider {
+ public:
+  UIStringOverrider();
+  UIStringOverrider(const uint32_t* resource_hashes,
+                                const int* resource_indices,
+                                size_t num_resources);
+  ~UIStringOverrider();
+
+  // Returns the resource index corresponding to the given hash or -1 if no
+  // resources is found. Visible for testing.
+  int GetResourceIndex(uint32_t hash);
+
+  // Overrides the string resource specified by |hash| with |string| in the
+  // resource bundle.
+  void OverrideUIString(uint32_t hash, const base::string16& string);
+
+ private:
+  const uint32_t* resource_hashes_;
+  const int* resource_indices_;
+  size_t num_resources_;

[Alexei Svitkine (slow), 2015/09/24 21:51:23]

Can you declare all of these as const? ie. so they're not changed after ctor
assignment.

const size_t
const uint32_t* const
etc.

[sdefresne, 2015/09/28 08:57:32]

Done.

+};
+
+}  // namespace variations
+
+#endif  // COMPONENTS_VARIATIONS_SERVICE_UI_STRING_OVERRIDER_H_