Create glue-layer TabModelOrchestrators

TabModelSelectorImpl does not create or destroy TabPersistentStore
anymore. Instead, TabModelOrchestrators manage the lifetime of TabModelSelectorImpl and
TabPersistentStore.

Give TabModelSelectorImpl a Supplier<TabPersistentStore> instead of
passing TabPersistentStore directly.

This is a step to break the two-way dependency between
TabModelSelectorImpl and TabPersistentStore.

Bug: 1138561
Change-Id: Ie2fa4a2735e509ff816b3e2cf5f8f6fffda7999c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572639
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Ella Ge <eirage@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835819}

chrome/android/chrome_java_sources.gni

@@ -86,8 +86,11 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/app/tabmodel/AsyncTabParamsManagerSingleton.java",
   "java/src/org/chromium/chrome/browser/app/tabmodel/ChromeNextTabPolicySupplier.java",
   "java/src/org/chromium/chrome/browser/app/tabmodel/ChromeTabModelFilterFactory.java",
+  "java/src/org/chromium/chrome/browser/app/tabmodel/CustomTabsTabModelOrchestrator.java",
   "java/src/org/chromium/chrome/browser/app/tabmodel/DefaultTabModelSelectorFactory.java",
+  "java/src/org/chromium/chrome/browser/app/tabmodel/TabModelOrchestrator.java",
   "java/src/org/chromium/chrome/browser/app/tabmodel/TabWindowManagerSingleton.java",
+  "java/src/org/chromium/chrome/browser/app/tabmodel/TabbedModeTabModelOrchestrator.java",
   "java/src/org/chromium/chrome/browser/app/video_tutorials/ChromeLanguageInfoProvider.java",
   "java/src/org/chromium/chrome/browser/app/video_tutorials/NewTabPageVideoIPHManager.java",
   "java/src/org/chromium/chrome/browser/app/video_tutorials/VideoPlayerActivity.java",

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

@@ -56,7 +56,9 @@ import org.chromium.chrome.browser.accessibility_tab_switcher.OverviewListLayout
 import org.chromium.chrome.browser.app.ChromeActivity;
 import org.chromium.chrome.browser.app.tabmodel.AsyncTabParamsManagerSingleton;
 import org.chromium.chrome.browser.app.tabmodel.ChromeNextTabPolicySupplier;
+import org.chromium.chrome.browser.app.tabmodel.TabModelOrchestrator;
 import org.chromium.chrome.browser.app.tabmodel.TabWindowManagerSingleton;
+import org.chromium.chrome.browser.app.tabmodel.TabbedModeTabModelOrchestrator;
 import org.chromium.chrome.browser.bookmarks.BookmarkUtils;
 import org.chromium.chrome.browser.compositor.CompositorViewHolder;
 import org.chromium.chrome.browser.compositor.bottombar.ephemeraltab.EphemeralTabCoordinator;
@@ -242,6 +244,7 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
 
     private ToolbarControlContainer mControlContainer;
 
+    private TabbedModeTabModelOrchestrator mTabModelOrchestrator;
     private TabModelSelectorImpl mTabModelSelectorImpl;
     private TabModelSelectorTabObserver mTabModelSelectorTabObserver;
     private TabModelSelectorTabModelObserver mTabModelObserver;
@@ -1601,7 +1604,13 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
     }
 
     @Override
-    protected TabModelSelector createTabModelSelector() {
+    protected TabModelOrchestrator createTabModelOrchestrator() {
+        mTabModelOrchestrator = new TabbedModeTabModelOrchestrator();
+        return mTabModelOrchestrator;
+    }
+
+    @Override
+    protected void createTabModels() {
         assert mTabModelSelectorImpl == null;
 
         Bundle savedInstanceState = getSavedInstanceState();
@@ -1612,17 +1621,15 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
         int index = savedInstanceState != null ? savedInstanceState.getInt(WINDOW_INDEX, 0) : 0;
 
         mNextTabPolicySupplier = new ChromeNextTabPolicySupplier(mOverviewModeBehaviorSupplier);
-        mTabModelSelectorImpl =
-                (TabModelSelectorImpl) TabWindowManagerSingleton.getInstance().requestSelector(
-                        this, this, mNextTabPolicySupplier, index);
-        if (mTabModelSelectorImpl == null) {
-            Toast.makeText(
-                         this, getString(R.string.unsupported_number_of_windows), Toast.LENGTH_LONG)
-                    .show();
+
+        boolean tabModelWasCreated =
+                mTabModelOrchestrator.createTabModels(this, this, mNextTabPolicySupplier, index);
+        if (!tabModelWasCreated) {
             finish();
-            return null;
+            return;
         }
 
+        mTabModelSelectorImpl = mTabModelOrchestrator.getTabModelSelector();
         mTabModelSelectorImpl.addObserver(new EmptyTabModelSelectorObserver() {
             @Override
             public void onTabStateInitialized() {
@@ -1646,8 +1653,6 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
         mAppIndexingUtil = new AppIndexingUtil(mTabModelSelectorImpl);
 
         if (startIncognito) mTabModelSelectorImpl.selectModel(true);
-
-        return mTabModelSelectorImpl;
     }
 
     @Override
@@ -2180,6 +2185,13 @@ public class ChromeTabbedActivity extends ChromeActivity<ChromeActivityComponent
         super.onDestroyInternal();
     }
 
+    @Override
+    protected void destroyTabModels() {
+        if (mTabModelOrchestrator != null) {
+            mTabModelOrchestrator.destroy();
+        }
+    }
+
     @Override
     public void onTrimMemory(int level) {
         super.onTrimMemory(level);

chrome/android/java/src/org/chromium/chrome/browser/app/ChromeActivity.java

@@ -69,6 +69,7 @@ import org.chromium.chrome.browser.app.flags.ChromeCachedFlags;
 import org.chromium.chrome.browser.app.tab_activity_glue.ReparentingDelegateFactory;
 import org.chromium.chrome.browser.app.tab_activity_glue.TabReparentingController;
 import org.chromium.chrome.browser.app.tabmodel.AsyncTabParamsManagerSingleton;
+import org.chromium.chrome.browser.app.tabmodel.TabModelOrchestrator;
 import org.chromium.chrome.browser.bookmarks.BookmarkBridge;
 import org.chromium.chrome.browser.bookmarks.BookmarkBridge.BookmarkItem;
 import org.chromium.chrome.browser.bookmarks.BookmarkModel;
@@ -239,7 +240,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
             new TabModelSelectorProfileSupplier(mTabModelSelectorSupplier);
     protected ObservableSupplierImpl<BookmarkBridge> mBookmarkBridgeSupplier =
             new ObservableSupplierImpl<>();
-    private TabModelSelector mTabModelSelector;
+    private TabModelOrchestrator mTabModelOrchestrator;
     private TabModelSelectorTabObserver mTabModelSelectorTabObserver;
     private TabCreator mRegularTabCreator;
     private TabCreator mIncognitoTabCreator;
@@ -261,7 +262,6 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
     /** Whether or not {@link #postDeferredStartupIfNeeded()} has already successfully run. */
     private boolean mDeferredStartupPosted;
 
-    private boolean mTabModelsInitialized;
     private boolean mNativeInitialized;
     private boolean mRemoveWindowBackgroundDone;
     protected AccessibilityVisibilityHandler mAccessibilityVisibilityHandler;
@@ -353,6 +353,9 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
         // onPreInflationStartup event.
         mComponent = createComponent();
 
+        // Create the orchestrator that manages Tab models and persistence
+        mTabModelOrchestrator = createTabModelOrchestrator();
+
         // There's no corresponding call to removeObserver() for this addObserver() because
         // mTabModelProfileSupplier has the same lifecycle as this activity.
         mTabModelProfileSupplier.addObserver((profile) -> {
@@ -478,9 +481,10 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
                     mCompositorViewHolder.getCompositorView());
 
             initializeTabModels();
+            TabModelSelector tabModelSelector = mTabModelOrchestrator.getTabModelSelector();
             setTabContentManager(new TabContentManager(this, getContentOffsetProvider(),
                     !SysUtils.isLowEndDevice(),
-                    mTabModelSelector != null ? mTabModelSelector::getTabById : null));
+                    tabModelSelector != null ? tabModelSelector::getTabById : null));
 
             if (!isFinishing()) {
                 getBrowserControlsManager().initialize(
@@ -642,28 +646,28 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      * this activity.
      */
     public final void initializeTabModels() {
-        if (mTabModelsInitialized) return;
+        if (mTabModelOrchestrator.areTabModelsInitialized()) return;
 
-        mTabModelSelector = createTabModelSelector();
+        createTabModels();
+        TabModelSelector tabModelSelector = mTabModelOrchestrator.getTabModelSelector();
 
-        if (mTabModelSelector == null) {
+        if (tabModelSelector == null) {
             assert isFinishing();
-            mTabModelsInitialized = true;
             return;
         }
 
-        mTabModelSelectorSupplier.set(mTabModelSelector);
-        mActivityTabProvider.setTabModelSelector(mTabModelSelector);
-        getStatusBarColorController().setTabModelSelector(mTabModelSelector);
+        mTabModelSelectorSupplier.set(tabModelSelector);
+        mActivityTabProvider.setTabModelSelector(tabModelSelector);
+        getStatusBarColorController().setTabModelSelector(tabModelSelector);
 
         Pair<? extends TabCreator, ? extends TabCreator> tabCreators = createTabCreators();
         mRegularTabCreator = tabCreators.first;
         mIncognitoTabCreator = tabCreators.second;
 
-        OfflinePageUtils.observeTabModelSelector(this, mTabModelSelector);
+        OfflinePageUtils.observeTabModelSelector(this, tabModelSelector);
         if (mTabModelSelectorTabObserver != null) mTabModelSelectorTabObserver.destroy();
 
-        mTabModelSelectorTabObserver = new TabModelSelectorTabObserver(mTabModelSelector) {
+        mTabModelSelectorTabObserver = new TabModelSelectorTabObserver(tabModelSelector) {
             @Override
             public void onLoadStopped(Tab tab, boolean toDifferentDocument) {
                 postDeferredStartupIfNeeded();
@@ -680,8 +684,6 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
                 postDeferredStartupIfNeeded();
             }
         };
-
-        mTabModelsInitialized = true;
     }
 
     /**
@@ -697,9 +699,19 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
     }
 
     /**
-     * @return The {@link TabModelSelector} owned by this {@link ChromeActivity}.
+     * @return The {@link TabModelOrchestrator} owned by this {@link ChromeActivity}.
+     */
+    protected abstract TabModelOrchestrator createTabModelOrchestrator();
+
+    /**
+     * Call the {@link TabModelOrchestrator} to initialize its members.
      */
-    protected abstract TabModelSelector createTabModelSelector();
+    protected abstract void createTabModels();
+
+    /**
+     * Call the {@link TabModelOrchestrator} to destroy its members.
+     */
+    protected abstract void destroyTabModels();
 
     /**
      * @return The {@link TabCreator}s owned
@@ -826,7 +838,8 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
         VrModuleProvider.getDelegate().onActivityHidden(this);
 
         Tab tab = getActivityTab();
-        if (mTabModelSelector != null && !mTabModelSelector.isReparentingInProgress()
+        TabModelSelector tabModelSelector = mTabModelOrchestrator.getTabModelSelector();
+        if (tabModelSelector != null && !tabModelSelector.isReparentingInProgress()
                 && tab != null) {
             tab.hide(TabHidingType.ACTIVITY_HIDDEN);
         }
@@ -1288,10 +1301,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
             mActivityTabStartupMetricsTracker = null;
         }
 
-        if (mTabModelsInitialized) {
-            TabModelSelector selector = getTabModelSelector();
-            if (selector != null) selector.destroy();
-        }
+        destroyTabModels();
 
         if (mBookmarkBridgeSupplier != null) {
             BookmarkBridge bookmarkBridge = mBookmarkBridgeSupplier.get();
@@ -1562,7 +1572,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      * @return Whether the tab models have been fully initialized.
      */
     public boolean areTabModelsInitialized() {
-        return mTabModelsInitialized;
+        return mTabModelOrchestrator.areTabModelsInitialized();
     }
 
     /**
@@ -1571,11 +1581,11 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      * @return The {@link TabModelSelector}, possibly null.
      */
     public TabModelSelector getTabModelSelector() {
-        if (!mTabModelsInitialized) {
+        if (!mTabModelOrchestrator.areTabModelsInitialized()) {
             throw new IllegalStateException(
                     "Attempting to access TabModelSelector before initialization");
         }
-        return mTabModelSelector;
+        return mTabModelOrchestrator.getTabModelSelector();
     }
 
     /**
@@ -1596,7 +1606,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
 
     @Override
     public TabCreator getTabCreator(boolean incognito) {
-        if (!mTabModelsInitialized) {
+        if (!mTabModelOrchestrator.areTabModelsInitialized()) {
             throw new IllegalStateException(
                     "Attempting to access TabCreator before initialization");
         }
@@ -1663,7 +1673,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      * null if the Tab does not exist or the system is not initialized.
      */
     public Tab getActivityTab() {
-        if (!mTabModelsInitialized) {
+        if (!mTabModelOrchestrator.areTabModelsInitialized()) {
             return null;
         }
         return TabModelUtils.getCurrentTab(getCurrentTabModel());
@@ -1674,7 +1684,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      *         WebContents.
      */
     public WebContents getCurrentWebContents() {
-        if (!mTabModelsInitialized) {
+        if (!mTabModelOrchestrator.areTabModelsInitialized()) {
             return null;
         }
         return TabModelUtils.getCurrentWebContents(getCurrentTabModel());
@@ -1997,7 +2007,7 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
 
         if (id == R.id.help_id) {
             String url = currentTab != null ? currentTab.getUrlString() : "";
-            Profile profile = mTabModelSelector.isIncognitoSelected()
+            Profile profile = getTabModelSelector().isIncognitoSelected()
                     ? Profile.getLastUsedRegularProfile().getPrimaryOTRProfile()
                     : Profile.getLastUsedRegularProfile();
             startHelpAndFeedback(url, "MobileMenuFeedback", profile);

chrome/android/java/src/org/chromium/chrome/browser/app/tabmodel/CustomTabsTabModelOrchestrator.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.app.tabmodel;
+
+import androidx.annotation.Nullable;
+
+import org.chromium.base.supplier.Supplier;
+import org.chromium.chrome.browser.dependency_injection.ActivityScope;
+import org.chromium.chrome.browser.tabmodel.AsyncTabParamsManager;
+import org.chromium.chrome.browser.tabmodel.NextTabPolicy;
+import org.chromium.chrome.browser.tabmodel.NextTabPolicy.NextTabPolicySupplier;
+import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
+import org.chromium.chrome.browser.tabmodel.TabModelFilterFactory;
+import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
+import org.chromium.chrome.browser.tabmodel.TabPersistencePolicy;
+import org.chromium.chrome.browser.tabmodel.TabPersistentStore;
+import org.chromium.ui.base.WindowAndroid;
+
+import javax.inject.Inject;
+
+/**
+ * Glue-level class that manages lifetime of root .tabmodel objects: {@link TabPersistentStore} and
+ * {@link TabModelSelectorImpl} for custom tabs.
+ */
+@ActivityScope
+public class CustomTabsTabModelOrchestrator extends TabModelOrchestrator {
+    @Inject
+    public CustomTabsTabModelOrchestrator() {}
+
+    /**
+     * Creates the TabModelSelector and the TabPersistentStore.
+     */
+    public void createTabModels(@Nullable Supplier<WindowAndroid> windowAndroidSupplier,
+            TabCreatorManager tabCreatorManager, TabModelFilterFactory tabModelFilterFactory,
+            TabPersistencePolicy persistencePolicy, AsyncTabParamsManager asyncTabParamsManager) {
+        // Instantiate TabModelSelectorImpl
+        NextTabPolicySupplier nextTabPolicySupplier = () -> NextTabPolicy.LOCATIONAL;
+        mTabModelSelector = new TabModelSelectorImpl(windowAndroidSupplier, tabCreatorManager,
+                tabModelFilterFactory, nextTabPolicySupplier, asyncTabParamsManager, false, false,
+                false);
+
+        // Instantiate TabPersistentStore
+        mTabPersistentStore =
+                new TabPersistentStore(persistencePolicy, mTabModelSelector, tabCreatorManager);
+
+        wireSelectorAndStore();
+        markTabModelsInitialized();
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/app/tabmodel/DefaultTabModelSelectorFactory.java

@@ -5,19 +5,15 @@
 package org.chromium.chrome.browser.app.tabmodel;
 
 import android.app.Activity;
-import android.os.Build;
 
 import org.chromium.base.annotations.VerifiesOnN;
-import org.chromium.chrome.browser.multiwindow.MultiInstanceManager;
-import org.chromium.chrome.browser.multiwindow.MultiWindowUtils;
+import org.chromium.chrome.browser.tabmodel.AsyncTabParamsManager;
 import org.chromium.chrome.browser.tabmodel.NextTabPolicy.NextTabPolicySupplier;
 import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
 import org.chromium.chrome.browser.tabmodel.TabModelFilterFactory;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorFactory;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
-import org.chromium.chrome.browser.tabmodel.TabPersistencePolicy;
-import org.chromium.chrome.browser.tabmodel.TabbedModeTabPersistencePolicy;
 
 /**
  * Default {@link TabModelSelectorFactory} for Chrome.
@@ -29,32 +25,11 @@ public class DefaultTabModelSelectorFactory implements TabModelSelectorFactory {
     @Override
     public TabModelSelector buildSelector(Activity activity, TabCreatorManager tabCreatorManager,
             NextTabPolicySupplier nextTabPolicySupplier, int selectorIndex) {
-        // Merge tabs if this TabModelSelector is for a ChromeTabbedActivity created in
-        // fullscreen mode and there are no TabModelSelector's currently alive. This indicates
-        // that it is a cold start or process restart in fullscreen mode.
-        boolean mergeTabs = Build.VERSION.SDK_INT > Build.VERSION_CODES.M
-                && MultiInstanceManager.isTabModelMergingEnabled()
-                && !activity.isInMultiWindowMode();
-        if (MultiInstanceManager.shouldMergeOnStartup(activity)) {
-            mergeTabs = mergeTabs
-                    && (!MultiWindowUtils.getInstance().isInMultiDisplayMode(activity)
-                            || TabWindowManagerSingleton.getInstance()
-                                            .getNumberOfAssignedTabModelSelectors()
-                                    == 0);
-        } else {
-            mergeTabs = mergeTabs
-                    && TabWindowManagerSingleton.getInstance()
-                                    .getNumberOfAssignedTabModelSelectors()
-                            == 0;
-        }
-        if (mergeTabs) {
-            MultiInstanceManager.mergedOnStartup();
-        }
-        TabPersistencePolicy persistencePolicy =
-                new TabbedModeTabPersistencePolicy(selectorIndex, mergeTabs);
         TabModelFilterFactory tabModelFilterFactory = new ChromeTabModelFilterFactory();
-        return new TabModelSelectorImpl(activity, /*windowAndroidSupplier=*/null, tabCreatorManager,
-                persistencePolicy, tabModelFilterFactory, nextTabPolicySupplier,
-                AsyncTabParamsManagerSingleton.getInstance(), true, true, false);
+        AsyncTabParamsManager asyncTabParamsManager = AsyncTabParamsManagerSingleton.getInstance();
+
+        return new TabModelSelectorImpl(/*windowAndroidSupplier=*/null, tabCreatorManager,
+                tabModelFilterFactory, nextTabPolicySupplier, asyncTabParamsManager, true, true,
+                false);
     }
 }

chrome/android/java/src/org/chromium/chrome/browser/app/tabmodel/TabModelOrchestrator.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.app.tabmodel;
+
+import org.chromium.base.supplier.ObservableSupplierImpl;
+import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
+import org.chromium.chrome.browser.tabmodel.TabPersistentStore;
+import org.chromium.chrome.browser.tabmodel.TabPersistentStore.TabPersistentStoreObserver;
+
+/**
+ * Implementers are glue-level objects that manage lifetime of root .tabmodel objects: {@link
+ * TabPersistentStore} and {@link TabModelSelectorImpl}.
+ */
+public abstract class TabModelOrchestrator {
+    protected TabPersistentStore mTabPersistentStore;
+    protected TabModelSelectorImpl mTabModelSelector;
+    private boolean mTabModelsInitialized;
+
+    /**
+     * @return Whether the tab models have been fully initialized.
+     */
+    public boolean areTabModelsInitialized() {
+        return mTabModelsInitialized;
+    }
+
+    /**
+     * @return The {@link TabModelSelectorImpl} managed by this orchestrator.
+     */
+    public TabModelSelectorImpl getTabModelSelector() {
+        return mTabModelSelector;
+    }
+
+    /**
+     * Destroy the {@link TabPersistentStore} and {@link TabModelSelectorImpl} members.
+     */
+    public void destroy() {
+        if (!mTabModelsInitialized) {
+            return;
+        }
+
+        if (mTabPersistentStore != null) {
+            mTabPersistentStore.destroy();
+            mTabPersistentStore = null;
+        }
+
+        if (mTabModelSelector != null) {
+            mTabModelSelector.destroy();
+            mTabModelSelector = null;
+        }
+
+        mTabModelsInitialized = false;
+    }
+
+    protected void wireSelectorAndStore() {
+        // Supply TabModelSelectorImpl with TabPersistentStore.
+        //
+        // TODO(crbug.com/1138561): Remove this dependency by making TabModelSelectorImpl emit
+        // events and TabPersistentStore react to them as an observer.
+        ObservableSupplierImpl<TabPersistentStore> tabPersistentStoreSupplier =
+                new ObservableSupplierImpl<>();
+        tabPersistentStoreSupplier.set(mTabPersistentStore);
+        mTabModelSelector.setTabPersistentStoreSupplier(tabPersistentStoreSupplier);
+
+        // Notify TabModelSelectorImpl when TabPersistentStore initializes tab state
+        final TabPersistentStoreObserver persistentStoreObserver =
+                new TabPersistentStoreObserver() {
+                    @Override
+                    public void onStateLoaded() {
+                        mTabModelSelector.markTabStateInitialized();
+                    }
+                };
+        mTabPersistentStore.addObserver(persistentStoreObserver);
+    }
+
+    protected void markTabModelsInitialized() {
+        mTabModelsInitialized = true;
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/app/tabmodel/TabbedModeTabModelOrchestrator.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.app.tabmodel;
+
+import android.app.Activity;
+import android.os.Build;
+
+import org.chromium.chrome.browser.multiwindow.MultiInstanceManager;
+import org.chromium.chrome.browser.multiwindow.MultiWindowUtils;
+import org.chromium.chrome.browser.tabmodel.NextTabPolicy.NextTabPolicySupplier;
+import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
+import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
+import org.chromium.chrome.browser.tabmodel.TabPersistencePolicy;
+import org.chromium.chrome.browser.tabmodel.TabPersistentStore;
+import org.chromium.chrome.browser.tabmodel.TabbedModeTabPersistencePolicy;
+import org.chromium.ui.widget.Toast;
+
+/**
+ * Glue-level class that manages lifetime of root .tabmodel objects: {@link TabPersistentStore} and
+ * {@link TabModelSelectorImpl} for tabbed mode.
+ */
+public class TabbedModeTabModelOrchestrator extends TabModelOrchestrator {
+    public TabbedModeTabModelOrchestrator() {}
+
+    /**
+     * Creates the TabModelSelector and the TabPersistentStore.
+     *
+     * @return Whether the creation was successful. It may fail is we reached the limit of number of
+     *         windows.
+     */
+    public boolean createTabModels(Activity activity, TabCreatorManager tabCreatorManager,
+            NextTabPolicySupplier nextTabPolicySupplier, int selectorIndex) {
+        boolean mergeTabs = shouldMergeTabs(activity);
+        if (mergeTabs) {
+            MultiInstanceManager.mergedOnStartup();
+        }
+
+        // Instantiate TabModelSelectorImpl
+        mTabModelSelector =
+                (TabModelSelectorImpl) TabWindowManagerSingleton.getInstance().requestSelector(
+                        activity, tabCreatorManager, nextTabPolicySupplier, selectorIndex);
+        if (mTabModelSelector == null) {
+            markTabModelsInitialized();
+            Toast.makeText(activity,
+                         activity.getString(
+                                 org.chromium.chrome.R.string.unsupported_number_of_windows),
+                         Toast.LENGTH_LONG)
+                    .show();
+            return false;
+        }
+
+        // Instantiate TabPersistentStore
+        TabPersistencePolicy tabPersistencePolicy =
+                new TabbedModeTabPersistencePolicy(selectorIndex, mergeTabs);
+        mTabPersistentStore =
+                new TabPersistentStore(tabPersistencePolicy, mTabModelSelector, tabCreatorManager);
+
+        wireSelectorAndStore();
+        markTabModelsInitialized();
+        return true;
+    }
+
+    private boolean shouldMergeTabs(Activity activity) {
+        // Merge tabs if this TabModelSelector is for a ChromeTabbedActivity created in
+        // fullscreen mode and there are no TabModelSelector's currently alive. This indicates
+        // that it is a cold start or process restart in fullscreen mode.
+        boolean mergeTabs = Build.VERSION.SDK_INT > Build.VERSION_CODES.M
+                && MultiInstanceManager.isTabModelMergingEnabled()
+                && !activity.isInMultiWindowMode();
+        if (MultiInstanceManager.shouldMergeOnStartup(activity)) {
+            mergeTabs = mergeTabs
+                    && (!MultiWindowUtils.getInstance().isInMultiDisplayMode(activity)
+                            || TabWindowManagerSingleton.getInstance()
+                                            .getNumberOfAssignedTabModelSelectors()
+                                    == 0);
+        } else {
+            mergeTabs = mergeTabs
+                    && TabWindowManagerSingleton.getInstance()
+                                    .getNumberOfAssignedTabModelSelectors()
+                            == 0;
+        }
+        return mergeTabs;
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/customtabs/BaseCustomTabActivity.java

@@ -24,6 +24,7 @@ import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeApplication;
 import org.chromium.chrome.browser.KeyboardShortcuts;
 import org.chromium.chrome.browser.app.ChromeActivity;
+import org.chromium.chrome.browser.app.tabmodel.TabModelOrchestrator;
 import org.chromium.chrome.browser.browserservices.BrowserServicesIntentDataProvider;
 import org.chromium.chrome.browser.browserservices.ui.controller.Verifier;
 import org.chromium.chrome.browser.browserservices.ui.trustedwebactivity.TrustedWebActivityCoordinator;
@@ -45,7 +46,6 @@ import org.chromium.chrome.browser.night_mode.SystemNightModeMonitor;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabState;
 import org.chromium.chrome.browser.tabmodel.ChromeTabCreator;
-import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
 import org.chromium.chrome.browser.theme.TopUiThemeColorProvider;
 import org.chromium.chrome.browser.ui.RootUiCoordinator;
@@ -293,8 +293,20 @@ public abstract class BaseCustomTabActivity extends ChromeActivity<BaseCustomTab
     }
 
     @Override
-    protected TabModelSelector createTabModelSelector() {
-        return mTabFactory.createTabModelSelector();
+    protected TabModelOrchestrator createTabModelOrchestrator() {
+        return mTabFactory.createTabModelOrchestrator();
+    }
+
+    @Override
+    protected void destroyTabModels() {
+        if (mTabFactory != null) {
+            mTabFactory.destroyTabModelOrchestrator();
+        }
+    }
+
+    @Override
+    protected void createTabModels() {
+        mTabFactory.createTabModels();
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/customtabs/content/CustomTabActivityTabFactory.java

@@ -15,6 +15,8 @@ import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.app.ChromeActivity;
 import org.chromium.chrome.browser.app.tabmodel.AsyncTabParamsManagerSingleton;
 import org.chromium.chrome.browser.app.tabmodel.ChromeTabModelFilterFactory;
+import org.chromium.chrome.browser.app.tabmodel.CustomTabsTabModelOrchestrator;
+import org.chromium.chrome.browser.app.tabmodel.TabModelOrchestrator;
 import org.chromium.chrome.browser.browserservices.BrowserServicesIntentDataProvider;
 import org.chromium.chrome.browser.customtabs.CustomTabDelegateFactory;
 import org.chromium.chrome.browser.customtabs.CustomTabTabPersistencePolicy;
@@ -26,7 +28,6 @@ import org.chromium.chrome.browser.tab.TabDelegateFactory;
 import org.chromium.chrome.browser.tab.TabLaunchType;
 import org.chromium.chrome.browser.tabmodel.AsyncTabParamsManager;
 import org.chromium.chrome.browser.tabmodel.ChromeTabCreator;
-import org.chromium.chrome.browser.tabmodel.NextTabPolicy;
 import org.chromium.chrome.browser.tabmodel.TabModelFilterFactory;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
@@ -56,7 +57,7 @@ public class CustomTabActivityTabFactory {
     private final Lazy<AsyncTabParamsManager> mAsyncTabParamsManager;
 
     @Nullable
-    private TabModelSelectorImpl mTabModelSelector;
+    private CustomTabsTabModelOrchestrator mTabModelOrchestrator;
 
     @Inject
     public CustomTabActivityTabFactory(ChromeActivity<?> activity,
@@ -77,21 +78,35 @@ public class CustomTabActivityTabFactory {
         mAsyncTabParamsManager = asyncTabParamsManager;
     }
 
-    /** Creates a {@link TabModelSelector} for the custom tab. */
-    public TabModelSelectorImpl createTabModelSelector() {
-        mTabModelSelector = new TabModelSelectorImpl(mActivity, mActivityWindowAndroid::get,
-                mActivity, mPersistencePolicy, mTabModelFilterFactory,
-                () -> NextTabPolicy.LOCATIONAL, mAsyncTabParamsManager.get(), false, false, false);
-        return mTabModelSelector;
+    /** Creates a {@link TabModelOrchestrator} for the custom tab. */
+    public TabModelOrchestrator createTabModelOrchestrator() {
+        mTabModelOrchestrator = new CustomTabsTabModelOrchestrator();
+        return mTabModelOrchestrator;
+    }
+
+    public void destroyTabModelOrchestrator() {
+        if (mTabModelOrchestrator != null) {
+            mTabModelOrchestrator.destroy();
+        }
+    }
+
+    /** Calls the {@link TabModelOrchestrator} to create TabModels and TabPersistentStore. */
+    public void createTabModels() {
+        mTabModelOrchestrator.createTabModels(mActivityWindowAndroid::get, mActivity,
+                mTabModelFilterFactory, mPersistencePolicy, mAsyncTabParamsManager.get());
     }
 
     /** Returns the previously created {@link TabModelSelector}. */
     public TabModelSelectorImpl getTabModelSelector() {
-        if (mTabModelSelector == null) {
+        if (mTabModelOrchestrator == null) {
+            assert false;
+            createTabModelOrchestrator();
+        }
+        if (mTabModelOrchestrator.getTabModelSelector() == null) {
             assert false;
-            return createTabModelSelector();
+            createTabModels();
         }
-        return mTabModelSelector;
+        return mTabModelOrchestrator.getTabModelSelector();
     }
 
     /** Creates a {@link ChromeTabCreator}s for the custom tab. */

chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicyTest.java

@@ -34,12 +34,11 @@ import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
 import org.chromium.chrome.browser.app.tabmodel.AsyncTabParamsManagerSingleton;
 import org.chromium.chrome.browser.app.tabmodel.ChromeTabModelFilterFactory;
+import org.chromium.chrome.browser.app.tabmodel.CustomTabsTabModelOrchestrator;
 import org.chromium.chrome.browser.compositor.layouts.content.TabContentManager;
 import org.chromium.chrome.browser.tab.MockTab;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabStateFileManager;
-import org.chromium.chrome.browser.tabmodel.NextTabPolicy;
-import org.chromium.chrome.browser.tabmodel.NextTabPolicy.NextTabPolicySupplier;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorImpl;
 import org.chromium.chrome.browser.tabmodel.TabPersistencePolicy;
@@ -456,12 +455,11 @@ public class CustomTabTabPersistencePolicyTest {
         CustomTabActivity activity = new CustomTabActivity();
         ApplicationStatus.onStateChangeForTesting(activity, ActivityState.CREATED);
 
-        NextTabPolicySupplier nextTabPolicySupplier = () -> NextTabPolicy.LOCATIONAL;
-
-        TabModelSelectorImpl selector = new TabModelSelectorImpl(activity,
-                activity::getWindowAndroid, activity, buildTestPersistencePolicy(),
-                new ChromeTabModelFilterFactory(), nextTabPolicySupplier,
-                AsyncTabParamsManagerSingleton.getInstance(), false, false, false);
+        CustomTabsTabModelOrchestrator orchestrator = new CustomTabsTabModelOrchestrator();
+        orchestrator.createTabModels(activity::getWindowAndroid, activity,
+                new ChromeTabModelFilterFactory(), buildTestPersistencePolicy(),
+                AsyncTabParamsManagerSingleton.getInstance());
+        TabModelSelectorImpl selector = orchestrator.getTabModelSelector();
         selector.initializeForTesting(normalTabModel, incognitoTabModel);
         ApplicationStatus.onStateChangeForTesting(activity, ActivityState.DESTROYED);
         return selector;

chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ContextMenuLoadUrlParamsTest.java

@@ -67,8 +67,7 @@ public class ContextMenuLoadUrlParamsTest {
 
         public RecordingTabModelSelector(Activity activity, TabCreatorManager tabCreatorManager,
                 TabModelFilterFactory tabModelFilterFactory, int selectorIndex) {
-            super(activity, null, tabCreatorManager,
-                    new TabbedModeTabPersistencePolicy(selectorIndex, false), tabModelFilterFactory,
+            super(null, tabCreatorManager, tabModelFilterFactory,
                     ()
                             -> NextTabPolicy.HIERARCHICAL,
                     AsyncTabParamsManagerSingleton.getInstance(), false, false, false);

chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/TabPersistentStoreTest.java

@@ -30,6 +30,7 @@ import org.chromium.chrome.browser.accessibility_tab_switcher.OverviewListLayout
 import org.chromium.chrome.browser.app.ChromeActivity;
 import org.chromium.chrome.browser.app.tabmodel.AsyncTabParamsManagerSingleton;
 import org.chromium.chrome.browser.app.tabmodel.ChromeTabModelFilterFactory;
+import org.chromium.chrome.browser.app.tabmodel.TabModelOrchestrator;
 import org.chromium.chrome.browser.app.tabmodel.TabWindowManagerSingleton;
 import org.chromium.chrome.browser.compositor.overlays.strip.StripLayoutHelper;
 import org.chromium.chrome.browser.flags.ActivityType;
@@ -237,10 +238,16 @@ public class TabPersistentStoreTest {
                 }
 
                 @Override
-                protected TabModelSelector createTabModelSelector() {
+                protected TabModelOrchestrator createTabModelOrchestrator() {
                     return null;
                 }
 
+                @Override
+                protected void createTabModels() {}
+
+                @Override
+                protected void destroyTabModels() {}
+
                 @Override
                 protected BrowserControlsManager createBrowserControlsManager() {
                     return null;

chrome/android/junit/src/org/chromium/chrome/browser/tabmodel/TabModelSelectorImplTest.java

@@ -8,8 +8,6 @@ import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 
-import android.app.Activity;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -17,7 +15,6 @@ import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.mockito.MockitoAnnotations;
-import org.robolectric.Robolectric;
 import org.robolectric.annotation.Config;
 
 import org.chromium.base.test.BaseRobolectricTestRunner;
@@ -37,8 +34,6 @@ import org.chromium.ui.base.WindowAndroid;
 @RunWith(BaseRobolectricTestRunner.class)
 @Config(manifest = Config.NONE)
 public class TabModelSelectorImplTest {
-    @Mock
-    TabPersistencePolicy mMockTabPersistencePolicy;
     @Mock
     TabModelFilterFactory mMockTabModelFilterFactory;
     @Mock
@@ -50,27 +45,22 @@ public class TabModelSelectorImplTest {
 
     private TabModelSelectorImpl mTabModelSelector;
     private MockTabCreatorManager mTabCreatorManager;
-    private Activity mActivity;
 
     @Before
     public void setUp() {
-        mActivity = Robolectric.buildActivity(Activity.class).setup().get();
         MockitoAnnotations.initMocks(this);
 
-        doReturn(TabPersistentStore.SAVED_STATE_FILE_PREFIX)
-                .when(mMockTabPersistencePolicy)
-                .getStateFileName();
-
         doReturn(mock(TabModelFilter.class))
                 .when(mMockTabModelFilterFactory)
                 .createTabModelFilter(any());
         mTabCreatorManager = new MockTabCreatorManager();
         AsyncTabParamsManager realAsyncTabParamsManager =
                 AsyncTabParamsManagerFactory.createAsyncTabParamsManager();
-        mTabModelSelector = new TabModelSelectorImpl(mActivity, null, mTabCreatorManager,
-                mMockTabPersistencePolicy, mMockTabModelFilterFactory, mNextTabPolicySupplier,
-                realAsyncTabParamsManager, /*supportUndo=*/false,
+        mTabModelSelector = new TabModelSelectorImpl(null, mTabCreatorManager,
+                mMockTabModelFilterFactory, mNextTabPolicySupplier, realAsyncTabParamsManager,
+                /*supportUndo=*/false,
                 /*isTabbedActivity=*/false, /*startIncognito=*/false);
+        mTabModelSelector.setTabPersistentStoreSupplier(() -> null);
         mTabCreatorManager.initialize(mTabModelSelector);
         mTabModelSelector.onNativeLibraryReadyInternal(mMockTabContentManager,
                 new MockTabModel(false, null), new MockTabModel(true, null));