Bug 1855977 - Set ExtensionProcessCrashObserver appInForeground flag to false if GeckoView is in background when Gecko main process is being started. r=geckoview-reviewers,willdurand,zmckenney

Differential Revision: https://phabricator.services.mozilla.com/D189680

mobile/android/components/geckoview/GeckoViewStartup.sys.mjs

@@ -249,6 +249,7 @@ export class GeckoViewStartup {
           "GeckoView:ResetUserPrefs",
           "GeckoView:SetDefaultPrefs",
           "GeckoView:SetLocale",
+          "GeckoView:InitialForeground",
         ]);
 
         Services.obs.addObserver(this, "browser-idle-startup-tasks-finished");
@@ -287,6 +288,16 @@ export class GeckoViewStartup {
     debug`onEvent ${aEvent}`;
 
     switch (aEvent) {
+      case "GeckoView:InitialForeground": {
+        // ExtensionProcessCrashObserver observes this topic to determine when
+        // the app goes into the foreground for the first time. This could be useful
+        // when the app is initially created in the background because, in this case,
+        // the "application-foreground" topic isn't notified when the application is
+        // moved into the foreground later. That is because "application-foreground"
+        // is only going to be notified when the application was first paused.
+        Services.obs.notifyObservers(null, "geckoview-initial-foreground");
+        break;
+      }
       case "GeckoView:ResetUserPrefs": {
         for (const name of aData.names) {
           Services.prefs.clearUserPref(name);

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoRuntime.java

@@ -166,6 +166,12 @@ public final class GeckoRuntime implements Parcelable {
         // Do not trigger the first onResume event because it breaks nsAppShell::sPauseCount counter
         // thresholds.
         GeckoThread.onResume();
+      } else {
+        // Notify Gecko when the application has been moved in the foreground for the first time
+        // after being created and started (used by the ExtensionProcessCrashObserver on the Gecko
+        // side to adjust the appIsForeground property when the application-foreground or
+        // application-background topics are not notified).
+        EventDispatcher.getInstance().dispatch("GeckoView:InitialForeground", null);
       }
       mPaused = false;
       // Can resume location services, checks if was in use before going to background

toolkit/components/extensions/Extension.sys.mjs

@@ -663,7 +663,14 @@ ExtensionAddonObserver.init();
 export var ExtensionProcessCrashObserver = {
   initialized: false,
 
-  _appInForeground: true,
+  // For Android apps we initially consider the app as always starting
+  // in the background, then we expect to be setting it to foreground
+  // when GeckoView LifecycleListener onResume method is called on the
+  // Android app first startup. After the application has got on the
+  // foreground for the first time then onPause/onResumed LifecycleListener
+  // are called, the application-foreground/-background topics will be
+  // notified to Gecko and this flag will be updated accordingly.
+  _appInForeground: AppConstants.platform !== "android",
   _isAndroid: AppConstants.platform === "android",
   _processSpawningDisabled: false,
 
@@ -687,6 +694,7 @@ export var ExtensionProcessCrashObserver = {
         "addons.process-crash-observer"
       );
       if (this._isAndroid) {
+        Services.obs.addObserver(this, "geckoview-initial-foreground");
         Services.obs.addObserver(this, "application-foreground");
         Services.obs.addObserver(this, "application-background");
       }
@@ -701,6 +709,7 @@ export var ExtensionProcessCrashObserver = {
         Services.obs.removeObserver(this, "process-type-set");
         Services.obs.removeObserver(this, "ipc:content-shutdown");
         if (this._isAndroid) {
+          Services.obs.removeObserver(this, "geckoview-initial-foreground");
           Services.obs.removeObserver(this, "application-foreground");
           Services.obs.removeObserver(this, "application-background");
         }
@@ -717,10 +726,21 @@ export var ExtensionProcessCrashObserver = {
   observe(subject, topic, data) {
     let childID = data;
     switch (topic) {
+      case "geckoview-initial-foreground":
+        this._appInForeground = true;
+        this.logger.debug(
+          `Detected Android application moved in the foreground (geckoview-initial-foreground)`
+        );
+        break;
       case "application-foreground":
       // Intentional fall-through
       case "application-background":
         this._appInForeground = topic === "application-foreground";
+        this.logger.debug(
+          `Detected Android application moved in the ${
+            this._appInForeground ? "foreground" : "background"
+          }`
+        );
         if (this._appInForeground) {
           Management.emit("application-foreground", {
             appInForeground: this._appInForeground,

toolkit/components/extensions/test/xpcshell/test_ext_background_early_shutdown.js

@@ -64,6 +64,30 @@ add_setup(function () {
   // Need a profile to init Glean.
   do_get_profile();
   Services.fog.initializeFOG();
+
+  Assert.equal(
+    ExtensionProcessCrashObserver.appInForeground,
+    AppConstants.platform !== "android",
+    "Expect appInForeground to be initially true on desktop and false on android builds"
+  );
+
+  // For Android build we mock the app moving in the foreground for the first time
+  // (which, in a real Fenix instance, happens when the application receives the first
+  // call to the onPause lifecycle callback and the geckoview-initial-foreground
+  // topic is being notified to Gecko as a side-effect of that).
+  //
+  // We have to mock the app moving in the foreground before any of the test extension
+  // startup, so that both Desktop and Mobile builds are in the same initial foreground
+  // state for the rest of the test file.
+  if (AppConstants.platform === "android") {
+    info("Mock geckoview-initial-foreground observer service topic");
+    ExtensionProcessCrashObserver.observe(null, "geckoview-initial-foreground");
+    Assert.equal(
+      ExtensionProcessCrashObserver.appInForeground,
+      true,
+      "Expect appInForeground to be true after geckoview-initial-foreground topic"
+    );
+  }
 });
 
 add_setup(

toolkit/components/extensions/test/xpcshell/test_process_crash_telemetry.js

@@ -24,6 +24,30 @@ add_setup(() => {
   // the call to testGetValue.
   Services.fog.initializeFOG();
   Services.fog.testResetFOG();
+
+  Assert.equal(
+    ExtensionProcessCrashObserver.appInForeground,
+    AppConstants.platform !== "android",
+    "Expect appInForeground to be initially true on desktop and false on android builds"
+  );
+
+  // For Android build we mock the app moving in the foreground for the first time
+  // (which, in a real Fenix instance, happens when the application receives the first
+  // call to the onPause lifecycle callback and the geckoview-initial-foreground
+  // topic is being notified to Gecko as a side-effect of that).
+  //
+  // We have to mock the app moving in the foreground before any of the test extension
+  // startup, so that both Desktop and Mobile builds are in the same initial foreground
+  // state for the rest of the test file.
+  if (AppConstants.platform === "android") {
+    info("Mock geckoview-initial-foreground observer service topic");
+    ExtensionProcessCrashObserver.observe(null, "geckoview-initial-foreground");
+    Assert.equal(
+      ExtensionProcessCrashObserver.appInForeground,
+      true,
+      "Expect appInForeground to be true after geckoview-initial-foreground topic"
+    );
+  }
 });
 
 add_task(async function test_process_crash_telemetry() {