Add feature flag for out-of-process print drivers

Interactions with print drivers via operating system APIs is being moved
from out of the highly privileged browser process into a sandboxed
utility service process.  Changes to support rolling this update out
will be guarded behind a feature flag "enable-oop-print-drivers".  This
feature is currently only applicable for desktop operating systems.

Bug: 809738
Change-Id: I938df469b6108a7b5a8dd9d5e0225d12bbe1f6af
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412449
Reviewed-by: Lei Zhang <[email protected]>
Commit-Queue: Alan Screen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#807363}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 94f2fbd..6afb426 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -2629,6 +2629,9 @@
 extern const char kEnableMediaFeedsBackgroundFetchName[];
 extern const char kEnableMediaFeedsBackgroundFetchDescription[];
 
+extern const char kEnableOopPrintDriversName[];
+extern const char kEnableOopPrintDriversDescription[];
+
 extern const char kRemoteCopyReceiverName[];
 extern const char kRemoteCopyReceiverDescription[];