Bug 1510979 - add a telemetry xpcshell-test for socket process r=janerik

We need a test-only IPC message to socket process to trigger the Telemetry::Scalar set since no js engine in the socket process.
And hook the IPC call to AddPendingEvent |CallOrWaitSocketProcess| introduced by bug 1496257.

Differential Revision: https://phabricator.services.mozilla.com/D14822

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

netwerk/base/nsINetUtil.idl

@@ -224,6 +224,11 @@ interface nsINetUtil : nsISupports
    */
   ACString getReferrerPolicyString(in unsigned long aPolicy);
 
+  /**
+   * This is test-only. Send an IPC message to let socket process send a
+   * telemetry.
+   */
+  void socketProcessTelemetryPing();
 
   /**
    * This is a void method that is C++ implemented and always

netwerk/base/nsIOService.cpp

@@ -507,6 +507,15 @@ RefPtr<MemoryReportingProcess> nsIOService::GetSocketProcessMemoryReporter() {
   return new SocketProcessMemoryReporter();
 }
 
+NS_IMETHODIMP
+nsIOService::SocketProcessTelemetryPing() {
+  CallOrWaitForSocketProcess([]() {
+    Unused << gIOService->mSocketProcess->GetActor()
+                  ->SendSocketProcessTelemetryPing();
+  });
+  return NS_OK;
+}
+
 NS_IMPL_ISUPPORTS(nsIOService, nsIIOService, nsINetUtil, nsISpeculativeConnect,
                   nsIObserver, nsIIOServiceInternal, nsISupportsWeakReference)
 

netwerk/ipc/PSocketProcess.ipdl

@@ -43,6 +43,8 @@ child:
   async SetOffline(bool offline);
   async InitSocketProcessBridgeParent(ProcessId processId, Endpoint<PSocketProcessBridgeParent> endpoint);
   async InitProfiler(Endpoint<PProfilerChild> aEndpoint);
+  // test-only
+  async SocketProcessTelemetryPing();
 };
 
 } // namespace net

netwerk/ipc/SocketProcessChild.cpp

@@ -151,6 +151,13 @@ mozilla::ipc::IPCResult SocketProcessChild::RecvInitProfiler(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult SocketProcessChild::RecvSocketProcessTelemetryPing() {
+  const uint32_t kExpectedUintValue = 42;
+  Telemetry::ScalarSet(Telemetry::ScalarID::TELEMETRY_TEST_SOCKET_ONLY_UINT,
+      kExpectedUintValue);
+  return IPC_OK();
+}
+
 void SocketProcessChild::DestroySocketProcessBridgeParent(ProcessId aId) {
   MOZ_ASSERT(NS_IsMainThread());
 

netwerk/ipc/SocketProcessChild.h

@@ -42,6 +42,7 @@ class SocketProcessChild final : public PSocketProcessChild {
       Endpoint<mozilla::net::PSocketProcessBridgeParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvInitProfiler(
       Endpoint<mozilla::PProfilerChild>&& aEndpoint) override;
+  mozilla::ipc::IPCResult RecvSocketProcessTelemetryPing() override;
 
   void CleanUp();
   void DestroySocketProcessBridgeParent(ProcessId aId);

toolkit/components/telemetry/tests/unit/test_SocketScalars.js

@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/
+*/
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+ChromeUtils.import("resource://gre/modules/TelemetryController.jsm");
+ChromeUtils.import("resource://testing-common/ContentTaskUtils.jsm");
+
+const SOCKET_ONLY_UINT_SCALAR = "telemetry.test.socket_only_uint";
+
+/**
+ * This function waits until socket scalars are reported into the
+ * scalar snapshot.
+ */
+async function waitForSocketScalars() {
+  await ContentTaskUtils.waitForCondition(() => {
+    const scalars = Telemetry.getSnapshotForScalars("main", false);
+    return Object.keys(scalars).includes("socket");
+  });
+}
+
+add_task(async function() {
+  if (!Services.prefs.getBoolPref("network.process.enabled")) {
+    Assert.ok(true, "Test finished: no point to test telemetry from socket process with lanuching the process");
+    return;
+  }
+
+  do_test_pending();
+
+  do_get_profile(true);
+  await TelemetryController.testSetup();
+
+  Services.netUtils.socketProcessTelemetryPing();
+
+  // Once scalars are set by the socket process, they don't immediately get
+  // sent to the parent process. Wait for the Telemetry IPC Timer to trigger
+  // and batch send the data back to the parent process.
+  await waitForSocketScalars();
+
+  Assert.equal(Telemetry.getSnapshotForScalars("main", false)
+                   .socket[SOCKET_ONLY_UINT_SCALAR],
+               42,
+               `${SOCKET_ONLY_UINT_SCALAR} must have the correct value (socket process).`);
+  do_test_finished();
+});
+

toolkit/components/telemetry/tests/unit/xpcshell.ini

@@ -67,6 +67,8 @@ skip-if = os == "android" # Disabled due to crashes (see bug 1331366)
 tags = addons
 [test_ChildScalars.js]
 skip-if = os == "android" # Disabled due to crashes (see bug 1331366)
+[test_SocketScalars.js]
+skip-if = os == "android"
 [test_TelemetryReportingPolicy.js]
 skip-if = os == "android" # Disabled due to crashes (see bug 1367762)
 tags = addons