Prevent hitting DCHECK when multiple slashes are specified in chrome://devtoo...

chrome/browser/dom_ui/chrome_url_data_manager.cc

Index: chrome/browser/dom_ui/chrome_url_data_manager.cc
===================================================================
--- chrome/browser/dom_ui/chrome_url_data_manager.cc	(revision 50559)
+++ chrome/browser/dom_ui/chrome_url_data_manager.cc	(working copy)
@@ -169,6 +169,13 @@
   if (i == Singleton<ChromeURLDataManager>()->file_sources_.end())
     return false;
 
+  // Check that |relative_path| is not an absolute path (otherwise AppendASCII()
+  // will DCHECK). The awkward use of StringType is because on some systems
+  // FilePath expects a std::string, but on others a std::wstring.
+  FilePath p(FilePath::StringType(relative_path.begin(), relative_path.end()));
+  if (p.IsAbsolute())
+    return false;
+
   *file_path = i->second.AppendASCII(relative_path);
 
   return true;