Move debug_devtools to a buildflag_header.

chrome/browser/devtools/devtools_window.cc

Index: chrome/browser/devtools/devtools_window.cc
diff --git a/chrome/browser/devtools/devtools_window.cc b/chrome/browser/devtools/devtools_window.cc
index 8387924d7ce284ea9421400114ca3e746aa767fc..04443805e50dc05850e8bbede8d612ea1db95615 100644
--- a/chrome/browser/devtools/devtools_window.cc
+++ b/chrome/browser/devtools/devtools_window.cc
@@ -51,6 +51,7 @@
 #include "content/public/common/content_client.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/escape.h"
+#include "third_party/WebKit/public/public_features.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/base/page_transition_types.h"
 #include "ui/events/keycodes/dom/keycode_converter.h"
@@ -209,9 +210,9 @@ GURL DecorateFrontendURL(const GURL& base_url) {
         switches::kDevToolsFlags);
   }
 
-#if defined(DEBUG_DEVTOOLS)
+#if BUILDFLAG(DEBUG_DEVTOOLS)
   url_string += "&debugFrontend=true";
-#endif  // defined(DEBUG_DEVTOOLS)
+#endif  // BUILDFLAG(DEBUG_DEVTOOLS)
 
   return GURL(url_string);
 }