Bug 1596101 - [remote] Forward Network.setUserAgentOverride to Emulation.setUserAgentOverride. r=remote-protocol-reviewers,maja_zf

The method under the Network domain is a redirect to
Emulation only. It might be deprecated, but that's unclear
in the current documentation.

Differential Revision: https://phabricator.services.mozilla.com/D52929

--HG--
extra : moz-landing-system : lando

remote/domains/parent/Network.jsm

@@ -75,6 +75,16 @@ class Network extends Domain {
     this.enabled = false;
   }
 
+  /**
+   * Allows overriding user agent with the given string.
+   *
+   * Redirected to Emulation.setUserAgentOverride.
+   */
+  setUserAgentOverride(options) {
+    const { id } = this.session;
+    this.session.execute(id, "Emulation", "setUserAgentOverride", options);
+  }
+
   _onRequest(eventName, httpChannel, data) {
     const topFrame = getLoadContext(httpChannel).topFrameElement;
     const request = {

remote/test/browser/emulation/browser_setUserAgentOverride.js

@@ -55,6 +55,59 @@ add_task(async function invalidUserAgent({ Emulation }) {
   ok(errorThrown, "Invalid user agent format raised error");
 });
 
+// Network.setUserAgentOverride is a redirect to Emulation.setUserAgentOverride.
+// Run duplicated tests for Network to ensure the redirect works.
+
+add_task(async function networkSetAndResetUserAgent({ Network }) {
+  const userAgent = "foo bar";
+
+  await loadURL(DOC);
+  isnot(
+    await getNavigatorProperty("userAgent"),
+    userAgent,
+    "Custom user agent hasn't been set"
+  );
+
+  try {
+    await Network.setUserAgentOverride({ userAgent });
+    await loadURL(DOC);
+    is(
+      await getNavigatorProperty("userAgent"),
+      userAgent,
+      "Custom user agent has been set"
+    );
+
+    await Network.setUserAgentOverride({ userAgent: "" });
+    await loadURL(DOC);
+    isnot(
+      await getNavigatorProperty("userAgent"),
+      userAgent,
+      "Custom user agent hasn't been set anymore"
+    );
+  } finally {
+    Services.prefs.clearUserPref("general.useragent.override");
+  }
+});
+
+add_task(async function networkInvalidUserAgent({ Network }) {
+  const userAgent = "foobar\n";
+
+  await loadURL(DOC);
+  isnot(
+    await getNavigatorProperty("userAgent"),
+    userAgent,
+    "Custom user agent hasn't been set"
+  );
+
+  let errorThrown = false;
+  try {
+    await Network.setUserAgentOverride({ userAgent });
+  } catch (e) {
+    errorThrown = true;
+  }
+  ok(errorThrown, "Invalid user agent format raised error");
+});
+
 async function getNavigatorProperty(prop) {
   return ContentTask.spawn(gBrowser.selectedBrowser, prop, _prop => {
     return content.navigator[_prop];