Expose LayoutManager as UnownedUserData

This patch adds a LayoutManagerProvider with a static method to access
the activity's LayoutManager. This patch has a fair amount of
indirection to keep certain apis internal and the public api clean.

LayoutManagerAppUtils: A utility class only exposed to app or glue
code to attach the LayoutManager to the window. This exists in its own
build target with ManagedLayoutManager.

ManagedLayoutManager: Another app/glue code api for lifecycle
management. This extends LayoutManager and includes other external
signals that would not otherwise be exposed through the LayoutManager
interface.

LayoutManagerProvider: This is the main access point for clients
wanting an instance of the LayoutManager.

LayoutManagerProvider.Unowned: A package-protected interface for
obscuring attach and detach method implementations in the public api.

Bug: 1161560, 1167255
Change-Id: Ie9561cd6d9dafcca8acac54a85c3c7bc27ca085e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2634003Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Mei Liang <meiliang@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846268}

chrome/android/BUILD.gn

@@ -350,6 +350,7 @@ android_library("chrome_java") {
     "//chrome/browser/ui/android/default_browser_promo:java",
     "//chrome/browser/ui/android/favicon:java",
     "//chrome/browser/ui/android/layouts:java",
+    "//chrome/browser/ui/android/layouts/glue:java",
     "//chrome/browser/ui/android/layouts/third_party/float_property:java",
     "//chrome/browser/ui/android/native_page:java",
     "//chrome/browser/ui/android/theme:java",

chrome/android/DEPS

@@ -12,7 +12,7 @@ include_rules = [
   "+chrome/browser/flags/android",
   "+chrome/browser/fullscreen/android",
   "+chrome/browser/image_descriptions",
-  "+chrome/browser/ui/android/layouts/java",
+  "+chrome/browser/ui/android/layouts",
   "+chrome/browser/notifications",
   "+chrome/browser/password_manager/android",
   "+chrome/browser/policy/android",

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

@@ -112,6 +112,7 @@ import org.chromium.chrome.browser.init.ProcessInitializationHandler;
 import org.chromium.chrome.browser.init.StartupTabPreloader;
 import org.chromium.chrome.browser.keyboard_accessory.ManualFillingComponent;
 import org.chromium.chrome.browser.keyboard_accessory.ManualFillingComponentFactory;
+import org.chromium.chrome.browser.layouts.LayoutManagerAppUtils;
 import org.chromium.chrome.browser.locale.LocaleManager;
 import org.chromium.chrome.browser.media.PictureInPictureController;
 import org.chromium.chrome.browser.metrics.ActivityTabStartupMetricsTracker;
@@ -1281,6 +1282,12 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
             mTabModelSelectorTabObserver = null;
         }
 
+        // TODO(1168131): Destruction and detaching of the LayoutManager should be moved to the
+        //                RootUiCoordinator.
+        if (mLayoutManagerSupplier.get() != null) {
+            LayoutManagerAppUtils.detach(mLayoutManagerSupplier.get());
+        }
+
         if (mCompositorViewHolder != null) {
             if (mCompositorViewHolder.getLayoutManager() != null) {
                 mCompositorViewHolder.getLayoutManager().removeSceneChangeObserver(this);
@@ -1789,6 +1796,9 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
     @Override
     public void initializeCompositorContent(LayoutManagerImpl layoutManager, View urlBar,
             ViewGroup contentContainer, ControlContainer controlContainer) {
+        // TODO(1168131): The responsibility of managing the availability of the LayoutManager
+        //                should be moved to the RootUiCoordinator.
+        LayoutManagerAppUtils.attach(getWindowAndroid(), layoutManager);
         mLayoutManagerSupplier.set(layoutManager);
 
         layoutManager.addSceneChangeObserver(this);

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManagerImpl.java

@@ -36,9 +36,9 @@ import org.chromium.chrome.browser.fullscreen.BrowserControlsManager;
 import org.chromium.chrome.browser.gesturenav.HistoryNavigationCoordinator;
 import org.chromium.chrome.browser.layouts.CompositorModelChangeProcessor;
 import org.chromium.chrome.browser.layouts.EventFilter;
-import org.chromium.chrome.browser.layouts.LayoutManager;
 import org.chromium.chrome.browser.layouts.LayoutStateProvider;
 import org.chromium.chrome.browser.layouts.LayoutType;
+import org.chromium.chrome.browser.layouts.ManagedLayoutManager;
 import org.chromium.chrome.browser.layouts.SceneOverlay;
 import org.chromium.chrome.browser.layouts.animation.CompositorAnimationHandler;
 import org.chromium.chrome.browser.layouts.components.VirtualView;
@@ -85,7 +85,7 @@ import java.util.Map;
  * A class that is responsible for managing an active {@link Layout} to show to the screen.  This
  * includes lifecycle managment like showing/hiding this {@link Layout}.
  */
-public class LayoutManagerImpl implements LayoutManager, LayoutUpdateHost, LayoutProvider,
+public class LayoutManagerImpl implements ManagedLayoutManager, LayoutUpdateHost, LayoutProvider,
                                           TabModelSelector.CloseAllTabsDelegate {
     /** Sampling at 60 fps. */
     private static final long FRAME_DELTA_TIME_MS = 16;
@@ -555,9 +555,7 @@ public class LayoutManagerImpl implements LayoutManager, LayoutUpdateHost, Layou
                 mTabModelFilterObserver);
     }
 
-    /**
-     * Cleans up and destroys this object.  It should not be used after this.
-     */
+    @Override
     public void destroy() {
         mAnimationHandler.destroy();
         mSceneChangeObservers.clear();

chrome/browser/ui/android/layouts/BUILD.gn

@@ -9,6 +9,7 @@ android_library("java") {
     "java/src/org/chromium/chrome/browser/layouts/CompositorModelChangeProcessor.java",
     "java/src/org/chromium/chrome/browser/layouts/EventFilter.java",
     "java/src/org/chromium/chrome/browser/layouts/LayoutManager.java",
+    "java/src/org/chromium/chrome/browser/layouts/LayoutManagerProvider.java",
     "java/src/org/chromium/chrome/browser/layouts/LayoutStateProvider.java",
     "java/src/org/chromium/chrome/browser/layouts/LayoutType.java",
     "java/src/org/chromium/chrome/browser/layouts/SceneOverlay.java",

chrome/browser/ui/android/layouts/glue/BUILD.gn

+# Copyright 2021 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.
+
+import("//build/config/android/rules.gni")
+
+android_library("java") {
+  visibility = [
+    ":*",
+    "//chrome/android:chrome_java",
+  ]
+
+  sources = [
+    "java/src/org/chromium/chrome/browser/layouts/LayoutManagerAppUtils.java",
+    "java/src/org/chromium/chrome/browser/layouts/ManagedLayoutManager.java",
+  ]
+
+  deps = [
+    "..:java",
+    "//ui/android:ui_java",
+  ]
+}

chrome/browser/ui/android/layouts/glue/java/src/org/chromium/chrome/browser/layouts/LayoutManagerAppUtils.java

+// Copyright 2021 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.layouts;
+
+import org.chromium.ui.base.WindowAndroid;
+
+/** A class used by app code to manage an instance of the {@link LayoutManager}. */
+public class LayoutManagerAppUtils {
+    /**
+     * Attach a shared {@link LayoutManager} to a {@link WindowAndroid}.
+     * @param windowAndroid The window to attach the manager to.
+     * @param controller The controller to attach.
+     */
+    public static void attach(WindowAndroid windowAndroid, ManagedLayoutManager controller) {
+        LayoutManagerProvider.attach(windowAndroid, controller);
+    }
+
+    /**
+     * Detach the specified {@link LayoutManager} from any {@link WindowAndroid}s it is associated
+     * with.
+     * @param controller The manager to remove from any associated windows.
+     */
+    public static void detach(ManagedLayoutManager controller) {
+        LayoutManagerProvider.detach(controller);
+    }
+}

chrome/browser/ui/android/layouts/glue/java/src/org/chromium/chrome/browser/layouts/ManagedLayoutManager.java

+// Copyright 2021 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.layouts;
+
+/**
+ * This interface is intended to be used by glue code to manage the lifecycle and external input to
+ * the {@link LayoutManager} implementations.
+ */
+public interface ManagedLayoutManager extends LayoutManagerProvider.Unowned {
+    /**
+     * Clean up any state held by the layout manager to prepare for browser shutdown. The object
+     * should not be used after this has been called.
+     */
+    void destroy();
+}

chrome/browser/ui/android/layouts/java/src/org/chromium/chrome/browser/layouts/LayoutManagerProvider.java

+// Copyright 2021 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.layouts;
+
+import org.chromium.base.UnownedUserData;
+import org.chromium.base.UnownedUserDataKey;
+import org.chromium.ui.base.WindowAndroid;
+
+/**
+ * This class manages the details associated with binding a {@link LayoutManager} to user data on a
+ * {@link WindowAndroid}.
+ */
+public class LayoutManagerProvider {
+    /** An interface that allows a LayoutManager to be associated with an unowned data host. */
+    interface Unowned extends LayoutManager, UnownedUserData {}
+
+    /** The key used to bind the LayoutManager to the unowned data host. */
+    private static final UnownedUserDataKey<Unowned> KEY = new UnownedUserDataKey<>(Unowned.class);
+
+    /**
+     * Get the shared {@link LayoutManager} from the provided {@link WindowAndroid}.
+     * @param windowAndroid The window to pull the LayoutManager from.
+     * @return A shared instance of a {@link LayoutManager}.
+     */
+    public static LayoutManager from(WindowAndroid windowAndroid) {
+        return KEY.retrieveDataFromHost(windowAndroid.getUnownedUserDataHost());
+    }
+
+    static void attach(WindowAndroid windowAndroid, Unowned layoutManager) {
+        KEY.attachToHost(windowAndroid.getUnownedUserDataHost(), layoutManager);
+    }
+
+    static void detach(Unowned layoutManager) {
+        KEY.detachFromAllHosts(layoutManager);
+    }
+}