Update uses of UTF conversions in content/ to use the base:: namespace.

content/browser/session_history_browsertest.cc

Index: content/browser/session_history_browsertest.cc
diff --git a/content/browser/session_history_browsertest.cc b/content/browser/session_history_browsertest.cc
index bec8293a6b83020f08a01db953eaa1f61802aa56..04d00da8512777b569fa04bff3113b20a1a9c672 100644
--- a/content/browser/session_history_browsertest.cc
+++ b/content/browser/session_history_browsertest.cc
@@ -99,7 +99,7 @@ class SessionHistoryTest : public ContentBrowserTest {
 
   void NavigateAndCheckTitle(const char* filename,
                              const std::string& expected_title) {
-    base::string16 expected_title16(ASCIIToUTF16(expected_title));
+    base::string16 expected_title16(base::ASCIIToUTF16(expected_title));
     TitleWatcher title_watcher(shell()->web_contents(), expected_title16);
     NavigateToURL(shell(), GetURL(filename));
     ASSERT_EQ(expected_title16, title_watcher.WaitAndGetTitle());