Refactor language detection logic to allow non-static CLD data sources.

components/translate/content/browser/browser_cld_utils.h

+// 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 COMPONENTS_TRANSLATE_CONTENT_BROWSER_BROWSER_CLD_UTILS_H_
+#define COMPONENTS_TRANSLATE_CONTENT_BROWSER_BROWSER_CLD_UTILS_H_
+
+#include "base/macros.h"
+
+namespace translate {
+
+// Browser-side utilities for dealing with CLD data source configuration.
+// This class exists primarily to avoid duplicating code in high-level targets
+// such as the Chrome browser, Chrome shell, and so on.
+class BrowserCldUtils {
+ public:
+  // Perform conditional configuration of the CLD data provider.
+  // If no specific BrowserCldDataProviderFactory has yet been set, an instance
+  // is created and assigned as appropriate for each platform. If a specific
+  // BrowserCldDataProviderFactory *has* been set, this method does nothing
+  // (as a side effect of setting the default factory, subsequent invocations
+  // do nothing - making this method reentrant).
+  //
+  // This method will not overwrite a data provider configured by an embedder.
+  // This method must be invoked prior to registering components with the
+  // component updater if the component updater implementation is to be used;
+  // it is best to ensure that this method is called as early as possible.
+  static void ConfigureDefaultDataProvider();
+
+ private:
+  BrowserCldUtils() {}
+  ~BrowserCldUtils() {}
+  DISALLOW_COPY_AND_ASSIGN(BrowserCldUtils);
+};
+
+}  // namespace translate
+
+#endif  // COMPONENTS_TRANSLATE_CONTENT_BROWSER_BROWSER_CLD_UTILS_H_