Mojo: Armed Watchers

ios/web/webui/mojo_facade_unittest.mm

Index: ios/web/webui/mojo_facade_unittest.mm
diff --git a/ios/web/webui/mojo_facade_unittest.mm b/ios/web/webui/mojo_facade_unittest.mm
index 542124c4a20567327c6e0454f454513381994130..cf7e5125bff2e7623299bd2eba2ac4a90990a2d9 100644
--- a/ios/web/webui/mojo_facade_unittest.mm
+++ b/ios/web/webui/mojo_facade_unittest.mm
@@ -199,6 +199,18 @@ TEST_F(MojoFacadeTest, Watch) {
                                  callback_id, MOJO_RESULT_OK];
   [[[evaluator() expect] andDo:^(NSInvocation*) {
     callback_received = true;
+
+    // Cancel the watch immediately to ensure there are no additional
+    // notifications.
+    NSDictionary* cancel_watch = @{
+      @"name" : @"support.cancelWatch",
+      @"args" : @{
+        @"watchId" : @(watch_id),
+      },
+    };
+    std::string result_as_string =
+        facade()->HandleMojoMessage(GetJson(cancel_watch));
+    EXPECT_TRUE(result_as_string.empty());
   }] executeJavaScript:expected_script completionHandler:nil];
 
   // Write to the other end of the pipe.