content: Move kHttpScheme constant into content namespace.

chrome/browser/ui/search_engines/search_engine_tab_helper.cc

Index: chrome/browser/ui/search_engines/search_engine_tab_helper.cc
diff --git a/chrome/browser/ui/search_engines/search_engine_tab_helper.cc b/chrome/browser/ui/search_engines/search_engine_tab_helper.cc
index d414510560717997984cdc4f51a7600e6cea4a27..dada154f1260e0f4d4da1f8fde748490947e05de 100644
--- a/chrome/browser/ui/search_engines/search_engine_tab_helper.cc
+++ b/chrome/browser/ui/search_engines/search_engine_tab_helper.cc
@@ -54,7 +54,7 @@ string16 GenerateKeywordFromNavigationEntry(const NavigationEntry* entry) {
   // If we relax the path constraint, we need to be sure to sanitize the path
   // elements and update AutocompletePopup to look for keywords using the path.
   // See http://b/issue?id=863583.
-  if (!url.SchemeIs(chrome::kHttpScheme) || (url.path().length() > 1))
+  if (!url.SchemeIs(content::kHttpScheme) || (url.path().length() > 1))
     return string16();
 
   return TemplateURLService::GenerateKeyword(url);