Add enable-stylus-keyboard flag definition

This will be used to hide away ongoing stylus keyboard work.

Bug: 824604
Change-Id: Iaa3aefc170e6d3a7633a08e7a0a0cd28d7ce19fb
Reviewed-on: https://chromium-review.googlesource.com/981572
Commit-Queue: Darren Shen <[email protected]>
Reviewed-by: Sadrul Chowdhury <[email protected]>
Cr-Commit-Position: refs/heads/master@{#546407}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 40ec81f..060cde9 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -1622,6 +1622,9 @@
 extern const char kEnableImeMenuName[];
 extern const char kEnableImeMenuDescription[];
 
+extern const char kEnableStylusVirtualKeyboardName[];
+extern const char kEnableStylusVirtualKeyboardDescription[];
+
 extern const char kEnableUnifiedMultiDeviceSettingsName[];
 extern const char kEnableUnifiedMultiDeviceSettingsDescription[];