Bump English spellcheck dictionary versions and add tests

chrome/common/spellcheck_common.cc

Index: chrome/common/spellcheck_common.cc
diff --git a/chrome/common/spellcheck_common.cc b/chrome/common/spellcheck_common.cc
index 73aeb86e0a33f1619730698ed4f4f670a8d05239..0a46f9f42d04979b61ab75ccab9ff39c5be7e657 100644
--- a/chrome/common/spellcheck_common.cc
+++ b/chrome/common/spellcheck_common.cc
@@ -105,14 +105,15 @@ FilePath GetVersionedFileName(const std::string& input_language,
     {"uk-UA", "-2-0"},
     {"pt-BR", "-2-2"},  // 2-2 (Mar 2011): upgraded a dictionary.
     {"sh",    "-2-2"},  // 2-2 (Mar 2011): added a dictionary.
-    {"en-US", "-2-3"},  // 2-3 (May 2012): fixed affixes + more words.
-    {"en-CA", "-2-3"},
-    {"en-GB", "-2-3"},
-    {"en-AU", "-2-3"},
     {"ca-ES", "-2-3"},  // 2-3 (May 2012): upgraded a dictionary.
     {"sv-SE", "-2-3"},  // 2-3 (May 2012): upgraded a dictionary.
     {"af-ZA", "-2-3"},  // 2-3 (May 2012): added a dictionary.
     {"fo-FO", "-2-3"},  // 2-3 (May 2012): added a dictionary.
+    {"en-US", "-2-4"},  // 2-4 (October 2012): add more words.
+    {"en-CA", "-2-4"},
+    {"en-GB", "-2-4"},
+    {"en-AU", "-2-4"},
+
   };
 
   // Generate the bdict file name using default version string or special