Move the number conversions from string_util to a new file.

Use the base namespace in the new file. Update callers.

I removed all wstring variants and also the string->number ones that ignore the return value. That encourages people to write code and forget about error handling.

TEST=included unit tests
BUG=none

Review URL: http://codereview.chromium.org/3056029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@54355 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/automation/automation_provider.cc b/chrome/browser/automation/automation_provider.cc
index f635916..9ee12d8 100644
--- a/chrome/browser/automation/automation_provider.cc
+++ b/chrome/browser/automation/automation_provider.cc
@@ -21,6 +21,7 @@
 #include "base/string_util.h"
 #include "base/task.h"
 #include "base/thread.h"
+#include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "base/waitable_event.h"
@@ -4334,7 +4335,7 @@
             }
             index++;
           }
-          *value = IntToString(found_index);
+          *value = base::IntToString(found_index);
           *success = true;
         }
         break;