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

content/renderer/media/rtc_dtmf_sender_handler.cc

Index: content/renderer/media/rtc_dtmf_sender_handler.cc
diff --git a/content/renderer/media/rtc_dtmf_sender_handler.cc b/content/renderer/media/rtc_dtmf_sender_handler.cc
index 3df592c8a6b0014a1ff92ebc5e6ba27a14282a85..23c5cc18f88b3e30d351243cd4aaf60329eba8ba 100644
--- a/content/renderer/media/rtc_dtmf_sender_handler.cc
+++ b/content/renderer/media/rtc_dtmf_sender_handler.cc
@@ -31,7 +31,7 @@ void RtcDtmfSenderHandler::setClient(
 }
 
 blink::WebString RtcDtmfSenderHandler::currentToneBuffer() {
-  return UTF8ToUTF16(dtmf_sender_->tones());
+  return base::UTF8ToUTF16(dtmf_sender_->tones());
 }
 
 bool RtcDtmfSenderHandler::canInsertDTMF() {
@@ -41,7 +41,7 @@ bool RtcDtmfSenderHandler::canInsertDTMF() {
 bool RtcDtmfSenderHandler::insertDTMF(const blink::WebString& tones,
                                       long duration,
                                       long interToneGap) {
-  std::string utf8_tones = UTF16ToUTF8(tones);
+  std::string utf8_tones = base::UTF16ToUTF8(tones);
   return dtmf_sender_->InsertDtmf(utf8_tones, static_cast<int>(duration),
                                   static_cast<int>(interToneGap));
 }
@@ -51,7 +51,7 @@ void RtcDtmfSenderHandler::OnToneChange(const std::string& tone) {
     LOG(ERROR) << "WebRTCDTMFSenderHandlerClient not set.";
     return;
   }
-  webkit_client_->didPlayTone(UTF8ToUTF16(tone));
+  webkit_client_->didPlayTone(base::UTF8ToUTF16(tone));
 }
 
 }  // namespace content