Added --enable-ui-devtools to chrome://flags.

BUG=678038

Review-Url: https://codereview.chromium.org/2928973003
Cr-Commit-Position: refs/heads/master@{#478258}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 8e14959356..87430a03 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -1348,6 +1348,9 @@
 extern const char kTouchscreenCalibrationName[];
 extern const char kTouchscreenCalibrationDescription[];
 
+extern const char kUiDevToolsName[];
+extern const char kUiDevToolsDescription[];
+
 extern const char kUseMusName[];
 extern const char kUseMusDescription[];
 extern const char kEnableMashDescription[];