terminal: support OSC 52 for copy for xterm.js

Bug: b/236205389
Change-Id: I90168ef268058d26f5abadeed966224962d32283
Reviewed-on: https://chromium-review.googlesource.com/c/apps/libapps/+/3864200
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/terminal/js/terminal_emulator_tests.js b/terminal/js/terminal_emulator_tests.js
index 1ad1794..e0f41ab 100644
--- a/terminal/js/terminal_emulator_tests.js
+++ b/terminal/js/terminal_emulator_tests.js
@@ -15,7 +15,12 @@
   describe('XtermTerminal', function() {
     beforeEach(async function() {
       this.mocks = {
-        term: new MockObject({options: {}}),
+        term: new MockObject({
+          options: {},
+          parser: {
+            registerOscHandler: () => {},
+          },
+        }),
         fontManager: new MockObject(),
         fitAddon: new MockObject(),
       };