Bug 1673316 - Ensure docShellIsActive is preserved when switching process. r=snorp

I'm not a fan of accessing private bits like `docShellIsActive` in tests like
that but it's both:

1) very important, if we don't correctly activate docShell performance will be
   very poor

2) stable, this API is not likely to change, and if it changes it
   should be easy to get whatever the replacement is

Differential Revision: https://phabricator.services.mozilla.com/D94874

mobile/android/chrome/geckoview/geckoview.js

@@ -186,9 +186,18 @@ var ModuleManager = {
     this.forEach(module => {
       module.onDestroyBrowser();
     });
+
+    // TODO: Bug 1673683: `docShellIsActive` is sometimes not preserved when
+    // switching process.
+    this.docShellIsActiveWhileSwitchingProcess = this.browser.docShellIsActive;
   },
 
   didChangeBrowserRemoteness() {
+    debug`DidChangeBrowserRemoteness`;
+
+    this.browser.docShellIsActive = this.docShellIsActiveWhileSwitchingProcess;
+    this.docShellIsActiveWhileSwitchingProcess = undefined;
+
     this.forEach(module => {
       if (module.impl) {
         module.impl.onInitBrowser();

mobile/android/geckoview/src/androidTest/assets/web_extensions/test-support/background.js

@@ -23,6 +23,9 @@ const APIS = {
   GetPrefs({ prefs }) {
     return browser.test.getPrefs(prefs);
   },
+  GetActive({ tab }) {
+    return browser.test.getActive(tab.id);
+  },
   RemoveCertOverride({ host, port }) {
     browser.test.removeCertOverride(host, port);
   },

mobile/android/geckoview/src/androidTest/assets/web_extensions/test-support/test-api.js

@@ -180,6 +180,11 @@ this.test = class extends ExtensionAPI {
           });
         },
 
+        async getActive(tabId) {
+          const tab = context.extension.tabManager.get(tabId);
+          return tab.browser.docShellIsActive;
+        },
+
         async flushApzRepaints(tabId) {
           const tab = context.extension.tabManager.get(tabId);
           const { browsingContext } = tab.browser;

mobile/android/geckoview/src/androidTest/assets/web_extensions/test-support/test-schema.json

@@ -133,6 +133,18 @@
           }
         ]
       },
+      {
+        "name": "getActive",
+        "type": "function",
+        "async": true,
+        "description": "Returns true if the docShell is active for given tab.",
+        "parameters": [
+          {
+            "type": "number",
+            "name": "tabId"
+          }
+        ]
+      },
       {
         "name": "getPidForTab",
         "type": "function",

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/BaseSessionTest.kt

@@ -191,6 +191,10 @@ open class BaseSessionTest(noErrorCollector: Boolean = false) {
 
     fun GeckoSession.flushApzRepaints() = sessionRule.flushApzRepaints(this)
 
+    var GeckoSession.active: Boolean
+            get() = sessionRule.getActive(this)
+            set(value) = setActive(value)
+
     @Suppress("UNCHECKED_CAST")
     fun Any?.asJsonArray(): JSONArray = this as JSONArray
 

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/NavigationDelegateTest.kt

@@ -1695,6 +1695,9 @@ class NavigationDelegateTest : BaseSessionTest() {
         mainSession.loadTestPath(HELLO2_HTML_PATH)
         sessionRule.waitForPageStop()
 
+        assertThat("docShell should start out active", mainSession.active,
+            equalTo(true))
+
         // This loads in the parent process
         mainSession.loadUri(url)
         sessionRule.waitForPageStop()
@@ -1706,6 +1709,9 @@ class NavigationDelegateTest : BaseSessionTest() {
         sessionRule.waitForPageStop()
 
         assertThat("URL should match", currentUrl!!, endsWith(HELLO_HTML_PATH))
+        assertThat("docShell should be active after switching process",
+                mainSession.active,
+                equalTo(true))
 
         mainSession.loadUri(url)
         sessionRule.waitForPageStop()
@@ -1716,6 +1722,9 @@ class NavigationDelegateTest : BaseSessionTest() {
         sessionRule.waitForPageStop()
 
         assertThat("URL should match", currentUrl!!, endsWith(HELLO_HTML_PATH))
+        assertThat("docShell should be active after switching process",
+                mainSession.active,
+                equalTo(true))
 
         sessionRule.session.goBack()
         sessionRule.waitForPageStop()
@@ -1726,6 +1735,9 @@ class NavigationDelegateTest : BaseSessionTest() {
         sessionRule.waitForPageStop()
 
         assertThat("URL should match", currentUrl!!, endsWith(HELLO2_HTML_PATH))
+        assertThat("docShell should be active after switching process",
+                mainSession.active,
+                equalTo(true))
 
         settings.aboutConfigEnabled = aboutConfigEnabled
     }

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/SessionLifecycleTest.kt

@@ -127,6 +127,8 @@ class SessionLifecycleTest : BaseSessionTest() {
         mainSession.loadTestPath(HELLO_HTML_PATH)
         mainSession.waitForPageStop()
 
+        assertThat("docShell should start active", mainSession.active, equalTo(true))
+
         // Deactivate the GeckoSession and confirm that rAF/setTimeout/etc callbacks do not run
         mainSession.setActive(false)
         mainSession.evaluateJS(
@@ -139,9 +141,13 @@ class SessionLifecycleTest : BaseSessionTest() {
         mainSession.waitForJS("new Promise(resolve => { resolve() })")
         val isNotGreen = mainSession.evaluateJS("document.documentElement.style.backgroundColor !== 'green'") as Boolean
         assertThat("requestAnimationFrame has not run yet", isNotGreen, equalTo(true))
+        assertThat("docShell shouldn't be active after calling setActive",
+                mainSession.active, equalTo(false))
 
         // Reactivate the GeckoSession and confirm that rAF/setTimeout/etc callbacks now run
         mainSession.setActive(true)
+        assertThat("docShell should be active after calling setActive(true)",
+                mainSession.active, equalTo(true))
         mainSession.waitForJS("new Promise(resolve => requestAnimationFrame(() => { resolve(); }))");
         var isGreen = mainSession.evaluateJS("document.documentElement.style.backgroundColor === 'green'") as Boolean
         assertThat("requestAnimationFrame has run", isGreen, equalTo(true))

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java

@@ -1911,6 +1911,12 @@ public class GeckoSessionTestRule implements TestRule {
         return dblPid.intValue();
     }
 
+    public boolean getActive(final @NonNull GeckoSession session) {
+        final Boolean isActive = (Boolean)
+                webExtensionApiCall(session, "GetActive", null);
+        return isActive;
+    }
+
     private Object waitForMessage(String id) {
         UiThreadUtils.waitForCondition(() -> mPendingMessages.containsKey(id),
                 mTimeoutMillis);