Update examples GYP to avoid rtc_base_approved warning.

webrtc/base/urlencode.h

Index: webrtc/base/urlencode.h
diff --git a/webrtc/base/urlencode.h b/webrtc/base/urlencode.h
index fc10f3880c531292afac24aecb546b1187c7a0f9..9aad43c7edca1d0a86f6af636433744ddc9570db 100644
--- a/webrtc/base/urlencode.h
+++ b/webrtc/base/urlencode.h
@@ -8,8 +8,8 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef _URLENCODE_H_
-#define _URLENCODE_H_ 
+#ifndef WEBRTC_BASE_URLENCODE_H_
+#define WEBRTC_BASE_URLENCODE_H_
 
 #include <string>
 
@@ -41,6 +41,6 @@ std::string UrlEncodeStringWithoutEncodingSpaceAsPlus(
     const std::string & decoded);
 std::string UrlEncodeStringForOnlyUnsafeChars(const std::string & decoded);
 
-#endif
+#endif  // WEBRTC_BASE_URLENCODE_H_
 
 }  // namespace rtc