--- a/toolkit/components/build/moz.build
+++ b/toolkit/components/build/moz.build
@@ -23,16 +23,17 @@ LOCAL_INCLUDES += [
     '../downloads',
     '../feeds',
     '../find',
     '../perfmonitoring',
     '../protobuf',
     '../reputationservice',
     '../startup',
     '../statusfilter',
+    '../telemetry',
     '../typeaheadfind',
     '../url-classifier',
 ]
 
 if not CONFIG['MOZ_DISABLE_PARENTAL_CONTROLS']:
     LOCAL_INCLUDES += [
         '../parentalcontrols',
     ]

--- a/toolkit/components/build/nsToolkitCompsCID.h
+++ b/toolkit/components/build/nsToolkitCompsCID.h
@@ -78,16 +78,21 @@
 #if defined(MOZ_UPDATER) && !defined(MOZ_WIDGET_ANDROID)
 #define NS_UPDATEPROCESSOR_CONTRACTID \
   "@mozilla.org/updates/update-processor;1"
 #endif
 
 #define NS_ADDONCONTENTPOLICY_CONTRACTID \
   "@mozilla.org/addons/content-policy;1"
 
+#if defined(ENABLE_TESTS)
+#define NS_TELEMETRYGECKOVIEWTESTING_CONTRACTID \
+  "@mozilla.org/telemetry/geckoview-testing;1"
+#endif
+
 /////////////////////////////////////////////////////////////////////////////
 
 #define ALERT_NOTIFICATION_CID \
 { 0x9a7b7a41, 0x0b47, 0x47f7, { 0xb6, 0x1b, 0x15, 0xa2, 0x10, 0xd6, 0xf0, 0x20 } }
 
 // {A0CCAAF8-09DA-44D8-B250-9AC3E93C8117}
 #define NS_ALERTSSERVICE_CID \
 { 0xa0ccaaf8, 0x9da, 0x44d8, { 0xb2, 0x50, 0x9a, 0xc3, 0xe9, 0x3c, 0x81, 0x17 } }
@@ -178,8 +183,13 @@
 #define NS_ADDONCONTENTPOLICY_CID \
 { 0xc26a8241, 0xecf4, 0x4aed, { 0x9f, 0x3c, 0xf1, 0xf5, 0xc7, 0x13, 0xb9, 0xa5 } }
 
 #define NS_ADDON_POLICY_SERVICE_CID \
 { 0x562de129, 0x8338, 0x482c, { 0xbb, 0x96, 0xa1, 0xff, 0x09, 0xee, 0x53, 0xcc } }
 
 #define NS_ADDON_POLICY_SERVICE_CONTRACTID \
   "@mozilla.org/addons/policy-service;1"
+
+#if defined(ENABLE_TESTS)
+#define NS_TELEMETRYGECKOVIEWTESTING_CID \
+  { 0xaaa3f7f2, 0x8ef0, 0x41ec, { 0x8d, 0x3, 0xae, 0xd6, 0x67, 0xcf, 0x7f, 0xa2 } };
+#endif

--- a/toolkit/components/build/nsToolkitCompsModule.cpp
+++ b/toolkit/components/build/nsToolkitCompsModule.cpp
@@ -54,16 +54,20 @@
 #endif
 
 #define MOZ_HAS_PERFSTATS
 
 #if defined(MOZ_HAS_PERFSTATS)
 #include "nsPerformanceStats.h"
 #endif // defined (MOZ_HAS_PERFSTATS)
 
+#if defined(ENABLE_TESTS)
+#include "geckoview/TelemetryGeckoViewTesting.h"
+#endif
+
 using namespace mozilla;
 
 /////////////////////////////////////////////////////////////////////////////
 
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsAppStartup, Init)
 
 #if defined(MOZ_HAS_PERFSTATS)
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsPerformanceStatsService, Init)
@@ -123,16 +127,20 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(NativeOSF
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(NativeFileWatcherService, Init)
 
 NS_GENERIC_FACTORY_CONSTRUCTOR(AddonContentPolicy)
 NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(AddonManagerStartup, AddonManagerStartup::GetInstance)
 NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(ExtensionPolicyService, ExtensionPolicyService::GetInstance)
 
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsSessionStoreUtils)
 
+#if defined(ENABLE_TESTS)
+NS_GENERIC_FACTORY_CONSTRUCTOR(TelemetryGeckoViewTestingImpl)
+#endif
+
 NS_DEFINE_NAMED_CID(NS_TOOLKIT_APPSTARTUP_CID);
 #if defined(MOZ_HAS_PERFSTATS)
 NS_DEFINE_NAMED_CID(NS_TOOLKIT_PERFORMANCESTATSSERVICE_CID);
 #endif // defined (MOZ_HAS_PERFSTATS)
 
 #if defined(MOZ_HAS_TERMINATOR)
 NS_DEFINE_NAMED_CID(NS_TOOLKIT_TERMINATOR_CID);
 #endif
@@ -157,16 +165,19 @@ NS_DEFINE_NAMED_CID(NS_UPDATEPROCESSOR_C
 #endif
 NS_DEFINE_NAMED_CID(FINALIZATIONWITNESSSERVICE_CID);
 NS_DEFINE_NAMED_CID(NATIVE_OSFILE_INTERNALS_SERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_ADDONCONTENTPOLICY_CID);
 NS_DEFINE_NAMED_CID(NS_ADDON_MANAGER_STARTUP_CID);
 NS_DEFINE_NAMED_CID(NS_ADDON_POLICY_SERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_SESSIONSTOREUTILS_CID);
 NS_DEFINE_NAMED_CID(NATIVE_FILEWATCHER_SERVICE_CID);
+#if defined(ENABLE_TESTS)
+NS_DEFINE_NAMED_CID(NS_TELEMETRYGECKOVIEWTESTING_CID);
+#endif
 
 static const Module::CIDEntry kToolkitCIDs[] = {
   { &kNS_TOOLKIT_APPSTARTUP_CID, false, nullptr, nsAppStartupConstructor },
 #if defined(MOZ_HAS_TERMINATOR)
   { &kNS_TOOLKIT_TERMINATOR_CID, false, nullptr, nsTerminatorConstructor },
 #endif
 #if defined(MOZ_HAS_PERFSTATS)
   { &kNS_TOOLKIT_PERFORMANCESTATSSERVICE_CID, false, nullptr, nsPerformanceStatsServiceConstructor },
@@ -192,16 +203,19 @@ static const Module::CIDEntry kToolkitCI
 #endif
   { &kFINALIZATIONWITNESSSERVICE_CID, false, nullptr, FinalizationWitnessServiceConstructor },
   { &kNATIVE_OSFILE_INTERNALS_SERVICE_CID, false, nullptr, NativeOSFileInternalsServiceConstructor },
   { &kNS_ADDONCONTENTPOLICY_CID, false, nullptr, AddonContentPolicyConstructor },
   { &kNS_ADDON_MANAGER_STARTUP_CID, false, nullptr, AddonManagerStartupConstructor },
   { &kNS_ADDON_POLICY_SERVICE_CID, false, nullptr, ExtensionPolicyServiceConstructor },
   { &kNS_SESSIONSTOREUTILS_CID, false, nullptr, nsSessionStoreUtilsConstructor },
   { &kNATIVE_FILEWATCHER_SERVICE_CID, false, nullptr, NativeFileWatcherServiceConstructor },
+#if defined(ENABLE_TESTS)
+  { &kNS_TELEMETRYGECKOVIEWTESTING_CID, false, nullptr, TelemetryGeckoViewTestingImplConstructor },
+#endif
   { nullptr }
 };
 
 static const Module::ContractIDEntry kToolkitContracts[] = {
   { NS_APPSTARTUP_CONTRACTID, &kNS_TOOLKIT_APPSTARTUP_CID },
 #if defined(MOZ_HAS_TERMINATOR)
   { NS_TOOLKIT_TERMINATOR_CONTRACTID, &kNS_TOOLKIT_TERMINATOR_CID },
 #endif
@@ -230,16 +244,19 @@ static const Module::ContractIDEntry kTo
 #endif
   { FINALIZATIONWITNESSSERVICE_CONTRACTID, &kFINALIZATIONWITNESSSERVICE_CID },
   { NATIVE_OSFILE_INTERNALS_SERVICE_CONTRACTID, &kNATIVE_OSFILE_INTERNALS_SERVICE_CID },
   { NS_ADDONCONTENTPOLICY_CONTRACTID, &kNS_ADDONCONTENTPOLICY_CID },
   { NS_ADDONMANAGERSTARTUP_CONTRACTID, &kNS_ADDON_MANAGER_STARTUP_CID },
   { NS_ADDON_POLICY_SERVICE_CONTRACTID, &kNS_ADDON_POLICY_SERVICE_CID },
   { NS_SESSIONSTOREUTILS_CONTRACTID, &kNS_SESSIONSTOREUTILS_CID },
   { NATIVE_FILEWATCHER_SERVICE_CONTRACTID, &kNATIVE_FILEWATCHER_SERVICE_CID },
+#if defined(ENABLE_TESTS)
+  { NS_TELEMETRYGECKOVIEWTESTING_CONTRACTID, &kNS_TELEMETRYGECKOVIEWTESTING_CID },
+#endif
   { nullptr }
 };
 
 static const mozilla::Module::CategoryEntry kToolkitCategories[] = {
   { "content-policy", NS_ADDONCONTENTPOLICY_CONTRACTID, NS_ADDONCONTENTPOLICY_CONTRACTID },
   { nullptr }
 };
 

new file mode 100644
--- /dev/null
+++ b/toolkit/components/telemetry/geckoview/TelemetryGeckoViewTesting.cpp
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TelemetryGeckoViewTesting.h"
+#include "TelemetryGeckoViewPersistence.h"
+
+namespace TelemetryGeckoViewTesting {
+  // This is defined in TelemetryGeckoViewPersistence.cpp
+  void TestDispatchPersist();
+} // TelemetryGeckoViewTesting
+
+NS_IMPL_ISUPPORTS(TelemetryGeckoViewTestingImpl, nsITelemetryGeckoViewTesting)
+
+// We don't need |aCx|. It's there to make these test functions harder
+// to call from C++.
+NS_IMETHODIMP
+TelemetryGeckoViewTestingImpl::InitPersistence(JSContext*)
+{
+  TelemetryGeckoViewPersistence::InitPersistence();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryGeckoViewTestingImpl::DeInitPersistence(JSContext*)
+{
+  TelemetryGeckoViewPersistence::DeInitPersistence();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryGeckoViewTestingImpl::ClearPersistenceData(JSContext*)
+{
+  TelemetryGeckoViewPersistence::ClearPersistenceData();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryGeckoViewTestingImpl::ForcePersist(JSContext*)
+{
+  TelemetryGeckoViewTesting::TestDispatchPersist();
+  return NS_OK;
+}

new file mode 100644
--- /dev/null
+++ b/toolkit/components/telemetry/geckoview/TelemetryGeckoViewTesting.h
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsITelemetryGeckoViewTesting.h"
+
+class TelemetryGeckoViewTestingImpl final : public nsITelemetryGeckoViewTesting
+{
+  ~TelemetryGeckoViewTestingImpl() = default;
+
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITELEMETRYGECKOVIEWTESTING
+};

new file mode 100644
--- /dev/null
+++ b/toolkit/components/telemetry/geckoview/nsITelemetryGeckoViewTesting.idl
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/**
+ * This is an internal interface used only for testing purposes.
+ *
+ * THIS IS NOT AN API TO BE USED BY EXTENSIONS! ONLY USED BY MOZILLA TESTS.
+ */
+[scriptable, builtinclass, uuid(019feb07-e5dd-48e6-aa59-fc98bcb65e7f)]
+interface nsITelemetryGeckoViewTesting : nsISupports
+{
+  /**
+   * The following methods map to the functions with the
+   * same name from TelemetryGeckoViewPersistence.cpp.
+   * Even though [implicit_jscontext] it's not needed on the methods,
+   * it's there to make it harder to call them from C++: this IDL is only
+   * meant to be used in xpcshell tests (JS).
+   */
+  [implicit_jscontext]
+  void initPersistence();
+  [implicit_jscontext]
+  void deInitPersistence();
+  [implicit_jscontext]
+  void clearPersistenceData();
+
+  /**
+   * Enqueues a persist action into the Telemetry persistence thread:
+   * measurements might be written to the disk after it returns.
+   */
+  [implicit_jscontext]
+  void forcePersist();
+};

--- a/toolkit/components/telemetry/moz.build
+++ b/toolkit/components/telemetry/moz.build
@@ -209,10 +209,21 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'andr
     # on platforms other than Android, since gtests on Android are not supported
     # yet (see bug 1318091).
     DEFINES['MOZ_TELEMETRY_GECKOVIEW'] = True
 
     EXTRA_JS_MODULES += [
         'geckoview/GeckoViewTelemetryController.jsm',
     ]
 
+# Include the GeckoView testing IDL if we're building tests
+# as well. This will be used in xpcshell tests.
+if CONFIG['ENABLE_TESTS']:
+    XPIDL_SOURCES += [
+        'geckoview/nsITelemetryGeckoViewTesting.idl'
+    ]
+
+    SOURCES += [
+        'geckoview/TelemetryGeckoViewTesting.cpp'
+    ]
+
 with Files('**'):
     BUG_COMPONENT = ('Toolkit', 'Telemetry')