Add Media Router result code for user cancellation

chrome/browser/media/router/mojo/media_router.mojom

Index: chrome/browser/media/router/mojo/media_router.mojom
diff --git a/chrome/browser/media/router/mojo/media_router.mojom b/chrome/browser/media/router/mojo/media_router.mojom
index e68a1e09f020fc35b6330550ea6cf52d1d67fcf8..943c416f6ae57193efd9a9792475202174283158 100644
--- a/chrome/browser/media/router/mojo/media_router.mojom
+++ b/chrome/browser/media/router/mojo/media_router.mojom
@@ -127,6 +127,7 @@ struct SinkSearchCriteria {
 // - RouteRequestResult::ResultCode in route_request_result.h
 // - MediaRouteProviderResult enum in tools/metrics/histograms.xml.
 // - mr.RouteRequestResultCode in route_request_error.js
+// - RouteRequestResultCodeFromMojo in media_router_type_converters.cc
 enum RouteRequestResultCode {
   UNKNOWN_ERROR,
   OK,
@@ -135,7 +136,8 @@ enum RouteRequestResultCode {
   SINK_NOT_FOUND,
   INVALID_ORIGIN,
   INCOGNITO_MISMATCH,
-  NO_SUPPORTED_PROVIDER
+  NO_SUPPORTED_PROVIDER,
+  CANCELLED
 // New values must be added here.
 };