Support GN configuration of enable_rlz (see issue #3404)

patch/patch.cfg

@@ -608,5 +608,10 @@ patches = [
     # chrome/browser/devtools/protocol/page_handler.cc.
     # https://bugs.chromium.org/p/chromium/issues/detail?id=1366011
     'name': 'chrome_browser_devtools_1366011'
+  },
+  {
+    # Support GN configuration of enable_rlz (see issue #3404).
+    # https://chromium-review.googlesource.com/c/chromium/src/+/3934411
+    'name': 'rlz_3934411'
   }
 ]

patch/patches/rlz_3934411.patch

@@ -0,0 +1,15 @@
+diff --git rlz/buildflags/buildflags.gni rlz/buildflags/buildflags.gni
+index 8090796ea3ec7..acfc599577296 100644
+--- rlz/buildflags/buildflags.gni
++++ rlz/buildflags/buildflags.gni
+@@ -9,4 +9,9 @@ import("//build/config/chromeos/ui_mode.gni")
+ # rlz codes for searches but do not use the library.
+ enable_rlz_support = is_win || is_apple || is_chromeos_ash
+ 
+-enable_rlz = is_chrome_branded && enable_rlz_support
++declare_args() {
++  enable_rlz = is_chrome_branded && enable_rlz_support
++}
++
++assert(!enable_rlz || enable_rlz_support,
++       "RLZ is only supported on Windows, Apple and ChromeOS Ash.")