[WebLayer] Create FragmentHostingRemoteFragmentImpl

This CL removes the fake FragmentActivity from SiteSettingsFragmentImpl
and MediaRouteDialogFragmentImpl, replacing them with a Context that
hosts the fragments instead. This is possible now that we've landed
the bytecode rewriting that changes the return type of
Fragment.getActivity() from FragmentActivity to Activity.

Bug: 1123216
Change-Id: I98c2c07eb348d6833ca2e5d976110f7f29b5359e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2523751
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Finnur Thorarinsson <finnur@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828649}

components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/AllSiteSettings.java

@@ -165,7 +165,7 @@ public class AllSiteSettings extends SiteSettingsPreferenceFragment
     /** OnClickListener for the clear button. We show an alert dialog to confirm the action */
     @Override
     public void onClick(View v) {
-        if (getActivity() == null || v != mClearButton) return;
+        if (getContext() == null || v != mClearButton) return;
 
         long totalUsage = 0;
         boolean includesApps = false;
@@ -181,9 +181,10 @@ public class AllSiteSettings extends SiteSettingsPreferenceFragment
             }
         }
 
-        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
-        View dialogView =
-                getActivity().getLayoutInflater().inflate(R.layout.clear_data_dialog, null);
+        AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
+        LayoutInflater inflater =
+                (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+        View dialogView = inflater.inflate(R.layout.clear_data_dialog, null);
         TextView message = dialogView.findViewById(android.R.id.message);
         TextView signedOutText = dialogView.findViewById(R.id.signed_out_text);
         TextView offlineText = dialogView.findViewById(R.id.offline_text);
@@ -192,7 +193,7 @@ public class AllSiteSettings extends SiteSettingsPreferenceFragment
         String dialogFormattedText =
                 getString(includesApps ? R.string.webstorage_clear_data_dialog_message_with_app
                                        : R.string.webstorage_clear_data_dialog_message,
-                        Formatter.formatShortFileSize(getActivity(), totalUsage));
+                        Formatter.formatShortFileSize(getContext(), totalUsage));
         message.setText(dialogFormattedText);
         builder.setView(dialogView);
         builder.setPositiveButton(R.string.storage_clear_dialog_clear_storage_option,
@@ -246,7 +247,7 @@ public class AllSiteSettings extends SiteSettingsPreferenceFragment
             MenuItem help = menu.add(
                     Menu.NONE, R.id.menu_id_site_settings_help, Menu.NONE, R.string.menu_help);
             help.setIcon(VectorDrawableCompat.create(
-                    getResources(), R.drawable.ic_help_and_feedback, getActivity().getTheme()));
+                    getResources(), R.drawable.ic_help_and_feedback, getContext().getTheme()));
         }
     }
 

components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/ChosenObjectSettings.java

@@ -122,7 +122,7 @@ public class ChosenObjectSettings extends SiteSettingsPreferenceFragment {
             MenuItem help = menu.add(
                     Menu.NONE, R.id.menu_id_site_settings_help, Menu.NONE, R.string.menu_help);
             help.setIcon(VectorDrawableCompat.create(
-                    getResources(), R.drawable.ic_help_and_feedback, getActivity().getTheme()));
+                    getResources(), R.drawable.ic_help_and_feedback, getContext().getTheme()));
         }
     }
 
@@ -166,7 +166,7 @@ public class ChosenObjectSettings extends SiteSettingsPreferenceFragment {
         // Managed objects cannot be revoked, so finish the activity only if the list did not
         // contain managed objects.
         if (hasManagedObject) {
-            ManagedPreferencesUtils.showManagedSettingsCannotBeResetToast(getActivity());
+            ManagedPreferencesUtils.showManagedSettingsCannotBeResetToast(getContext());
         } else {
             getActivity().finish();
         }
@@ -240,7 +240,7 @@ public class ChosenObjectSettings extends SiteSettingsPreferenceFragment {
         header.setTitle(titleText);
         header.setImageView(R.drawable.ic_delete_white_24dp,
                 R.string.website_settings_revoke_all_permissions_for_device, (View view) -> {
-                    new AlertDialog.Builder(getActivity(), R.style.Theme_Chromium_AlertDialog)
+                    new AlertDialog.Builder(getContext(), R.style.Theme_Chromium_AlertDialog)
                             .setTitle(R.string.reset)
                             .setMessage(dialogMsg)
                             .setPositiveButton(R.string.reset,

components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java

@@ -363,7 +363,7 @@ public class SingleCategorySettings extends SiteSettingsPreferenceFragment
             MenuItem help = menu.add(
                     Menu.NONE, R.id.menu_id_site_settings_help, Menu.NONE, R.string.menu_help);
             help.setIcon(VectorDrawableCompat.create(
-                    getResources(), R.drawable.ic_help_and_feedback, getActivity().getTheme()));
+                    getResources(), R.drawable.ic_help_and_feedback, getContext().getTheme()));
         }
     }
 
@@ -588,8 +588,7 @@ public class SingleCategorySettings extends SiteSettingsPreferenceFragment
 
         String hostname = primaryPattern.equals(SITE_WILDCARD) ? secondaryPattern : primaryPattern;
         Toast.makeText(getActivity(),
-                     String.format(
-                             getActivity().getString(R.string.website_settings_add_site_toast),
+                     String.format(getContext().getString(R.string.website_settings_add_site_toast),
                              hostname),
                      Toast.LENGTH_SHORT)
                 .show();
@@ -791,7 +790,7 @@ public class SingleCategorySettings extends SiteSettingsPreferenceFragment
             extras.putString(EXTRA_TITLE, getActivity().getTitle().toString());
             extras.putSerializable(ChosenObjectSettings.EXTRA_OBJECT_INFOS, entry.first);
             extras.putSerializable(ChosenObjectSettings.EXTRA_SITES, entry.second);
-            preference.setIcon(SettingsUtils.getTintedIcon(getActivity(),
+            preference.setIcon(SettingsUtils.getTintedIcon(getContext(),
                     ContentSettingsResources.getIcon(mCategory.getContentSettingsType())));
             preference.setTitle(entry.first.get(0).getName());
             preference.setFragment(ChosenObjectSettings.class.getCanonicalName());
@@ -1061,7 +1060,7 @@ public class SingleCategorySettings extends SiteSettingsPreferenceFragment
         descriptions[1] =
                 getString(ContentSettingsResources.getSiteSummary(ContentSettingValues.BLOCK));
 
-        return new AlertDialog.Builder(getActivity(), R.style.Theme_Chromium_AlertDialog)
+        return new AlertDialog.Builder(getContext(), R.style.Theme_Chromium_AlertDialog)
                 .setPositiveButton(R.string.cancel, null)
                 .setNegativeButton(R.string.remove,
                         (dialog, which) -> {

components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java

@@ -227,7 +227,7 @@ public class SingleWebsiteSettings extends SiteSettingsPreferenceFragment
 
     @Override
     public void onActivityCreated(Bundle savedInstanceState) {
-        getActivity().setTitle(R.string.prefs_site_settings);
+        getActivity().setTitle(getContext().getString(R.string.prefs_site_settings));
         init();
         super.onActivityCreated(savedInstanceState);
     }
@@ -358,7 +358,7 @@ public class SingleWebsiteSettings extends SiteSettingsPreferenceFragment
             @ContentSettingValues @Nullable Integer value, boolean enabled) {
         Drawable icon = enabled
                 ? SettingsUtils.getTintedIcon(
-                        getActivity(), ContentSettingsResources.getIcon(contentSettingsType))
+                        getContext(), ContentSettingsResources.getIcon(contentSettingsType))
                 : ContentSettingsResources.getDisabledIcon(contentSettingsType, getResources());
         if (getSiteSettingsClient().isPageInfoV2Enabled() && value != null
                 && value == ContentSettingValues.BLOCK) {
@@ -691,8 +691,8 @@ public class SingleWebsiteSettings extends SiteSettingsPreferenceFragment
                     new ChromeImageViewPreference(getStyledContext());
 
             preference.setKey(CHOOSER_PERMISSION_PREFERENCE_KEY);
-            preference.setIcon(SettingsUtils.getTintedIcon(getActivity(),
-                    ContentSettingsResources.getIcon(info.getContentSettingsType())));
+            preference.setIcon(SettingsUtils.getTintedIcon(
+                    getContext(), ContentSettingsResources.getIcon(info.getContentSettingsType())));
             preference.setOrder(maxPermissionOrder);
             preference.setTitle(info.getName());
             preference.setImageView(R.drawable.ic_delete_white_24dp,
@@ -1076,7 +1076,7 @@ public class SingleWebsiteSettings extends SiteSettingsPreferenceFragment
                 : R.string.website_reset_confirmation;
         int buttonResId = mHideNonPermissionPreferences ? R.string.reset : titleResId;
         // Handle the Clear & Reset preference click by showing a confirmation.
-        new AlertDialog.Builder(getActivity(), R.style.Theme_Chromium_AlertDialog)
+        new AlertDialog.Builder(getContext(), R.style.Theme_Chromium_AlertDialog)
                 .setTitle(titleResId)
                 .setMessage(confirmationResId)
                 .setPositiveButton(buttonResId,
@@ -1154,7 +1154,7 @@ public class SingleWebsiteSettings extends SiteSettingsPreferenceFragment
         mObjectUserPermissionCount = 0;
 
         if (mObjectPolicyPermissionCount > 0) {
-            ManagedPreferencesUtils.showManagedSettingsCannotBeResetToast(getActivity());
+            ManagedPreferencesUtils.showManagedSettingsCannotBeResetToast(getContext());
         }
     }
 }

components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SiteSettings.java

@@ -31,7 +31,7 @@ public class SiteSettings
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
         SettingsUtils.addPreferencesFromResource(this, R.xml.site_settings_preferences);
-        getActivity().setTitle(R.string.prefs_site_settings);
+        getActivity().setTitle(getContext().getString(R.string.prefs_site_settings));
 
         configurePreferences();
         updatePreferenceStates();
@@ -120,7 +120,7 @@ public class SiteSettings
 
             if (p.isEnabled()) {
                 p.setIcon(SettingsUtils.getTintedIcon(
-                        getActivity(), ContentSettingsResources.getIcon(contentType)));
+                        getContext(), ContentSettingsResources.getIcon(contentType)));
             } else {
                 p.setIcon(ContentSettingsResources.getDisabledIcon(contentType, getResources()));
             }

weblayer/browser/java/BUILD.gn

@@ -123,6 +123,7 @@ android_library("java") {
     "org/chromium/weblayer_private/ExternalNavigationDelegateImpl.java",
     "org/chromium/weblayer_private/FaviconCallbackProxy.java",
     "org/chromium/weblayer_private/FragmentAndroidPermissionDelegate.java",
+    "org/chromium/weblayer_private/FragmentHostingRemoteFragmentImpl.java",
     "org/chromium/weblayer_private/FragmentWindowAndroid.java",
     "org/chromium/weblayer_private/FullscreenCallbackProxy.java",
     "org/chromium/weblayer_private/FullscreenToast.java",

weblayer/browser/java/org/chromium/weblayer_private/FragmentHostingRemoteFragmentImpl.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.weblayer_private;
+
+import android.content.Context;
+import android.content.ContextWrapper;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.Handler;
+import android.util.AttributeSet;
+import android.view.InflateException;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewStub;
+
+import androidx.appcompat.app.AppCompatDelegate;
+import androidx.fragment.app.FragmentController;
+import androidx.fragment.app.FragmentHostCallback;
+import androidx.fragment.app.FragmentManager;
+
+import org.chromium.weblayer_private.interfaces.IRemoteFragmentClient;
+import org.chromium.weblayer_private.interfaces.StrictModeWorkaround;
+
+import java.lang.reflect.Constructor;
+
+/**
+ * A base class for RemoteFragmentImpls that need to host child Fragments.
+ *
+ * Because Fragments created in WebLayer use the AndroidX library from WebLayer's ClassLoader, we
+ * can't attach Fragments created here directly to the embedder's Fragment tree, and have to create
+ * a local FragmentController to manage them. This class handles creating the FragmentController,
+ * and forwards all Fragment lifecycle events from the RemoteFragment in the embedder's Fragment
+ * tree to child Fragments of this class.
+ */
+public abstract class FragmentHostingRemoteFragmentImpl extends RemoteFragmentImpl {
+    // The WebLayer-wrapped context object. This context gets assets and resources from WebLayer,
+    // not from the embedder. Use this for the most part, especially to resolve WebLayer-specific
+    // resource IDs.
+    private Context mContext;
+
+    private boolean mStarted;
+    private FragmentController mFragmentController;
+
+    protected static class RemoteFragmentContext
+            extends ContextWrapper implements LayoutInflater.Factory2 {
+        private static final Class<?>[] VIEW_CONSTRUCTOR_ARGS =
+                new Class[] {Context.class, AttributeSet.class};
+
+        public RemoteFragmentContext(Context webLayerContext) {
+            super(webLayerContext);
+
+            // Register ourselves as a the LayoutInflater factory so we can handle loading Views.
+            // See onCreateView for information about why this is needed.
+            if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
+                getLayoutInflater().setFactory2(this);
+            }
+        }
+
+        // This method is needed to work around a LayoutInflater bug in Android <N.  Before
+        // LayoutInflater creates an instance of a View, it needs to look up the class by name to
+        // get a reference to its Constructor. As an optimization, it caches this name to
+        // Constructor mapping. This cache causes issues if a class gets loaded multiple times with
+        // different ClassLoaders. In some UIs, some AndroidX Views get loaded early on with the
+        // embedding app's ClassLoader, so the Constructor from that ClassLoader's version of the
+        // class gets cached. When the WebLayer implementation later tries to inflate the same
+        // class, it instantiates a version from the wrong ClassLoader, which leads to a
+        // ClassCastException when casting that View to its original class. This was fixed in
+        // Android N, but to work around it on L & M, we inflate the Views manually here, which
+        // bypasses LayoutInflater's cache.
+        @Override
+        public View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
+            // If the class doesn't have a '.' in its name, it's probably a built-in Android View,
+            // which are often referenced by just their class names with no package prefix. For
+            // these classes we can return null to fall back to LayoutInflater's default behavior.
+            if (name.indexOf('.') == -1) {
+                return null;
+            }
+
+            Class<? extends View> clazz = null;
+            try {
+                clazz = context.getClassLoader().loadClass(name).asSubclass(View.class);
+                LayoutInflater inflater = getLayoutInflater();
+                if (inflater.getFilter() != null && !inflater.getFilter().onLoadClass(clazz)) {
+                    throw new InflateException(attrs.getPositionDescription()
+                            + ": Class not allowed to be inflated " + name);
+                }
+
+                Constructor<? extends View> constructor =
+                        clazz.getConstructor(VIEW_CONSTRUCTOR_ARGS);
+                constructor.setAccessible(true);
+                View view = constructor.newInstance(new Object[] {context, attrs});
+                if (view instanceof ViewStub) {
+                    // Use the same Context when inflating ViewStub later.
+                    ViewStub viewStub = (ViewStub) view;
+                    viewStub.setLayoutInflater(inflater.cloneInContext(context));
+                }
+                return view;
+            } catch (Exception e) {
+                InflateException ie = new InflateException(attrs.getPositionDescription()
+                        + ": Error inflating class "
+                        + (clazz == null ? "<unknown>" : clazz.getName()));
+                ie.initCause(e);
+                throw ie;
+            }
+        }
+
+        @Override
+        public View onCreateView(String name, Context context, AttributeSet attrs) {
+            return null;
+        }
+
+        private LayoutInflater getLayoutInflater() {
+            return (LayoutInflater) getBaseContext().getSystemService(
+                    Context.LAYOUT_INFLATER_SERVICE);
+        }
+    }
+
+    private static class RemoteFragmentHostCallback extends FragmentHostCallback<Context> {
+        private final FragmentHostingRemoteFragmentImpl mFragmentImpl;
+
+        private RemoteFragmentHostCallback(FragmentHostingRemoteFragmentImpl fragmentImpl) {
+            super(fragmentImpl.getWebLayerContext(), new Handler(), 0);
+            mFragmentImpl = fragmentImpl;
+        }
+
+        @Override
+        public Context onGetHost() {
+            return mFragmentImpl.getWebLayerContext();
+        }
+
+        @Override
+        public LayoutInflater onGetLayoutInflater() {
+            Context context = mFragmentImpl.getWebLayerContext();
+            return ((LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE))
+                    .cloneInContext(context);
+        }
+
+        @Override
+        public boolean onHasView() {
+            return mFragmentImpl.getView() != null;
+        }
+
+        @Override
+        public View onFindViewById(int id) {
+            return onHasView() ? mFragmentImpl.getView().findViewById(id) : null;
+        }
+    }
+
+    protected FragmentHostingRemoteFragmentImpl(IRemoteFragmentClient remoteFragmentClient) {
+        super(remoteFragmentClient);
+    }
+
+    @Override
+    public void onAttach(Context embedderContext) {
+        StrictModeWorkaround.apply();
+        super.onAttach(embedderContext);
+
+        mContext = createRemoteFragmentContext(embedderContext);
+        mFragmentController =
+                FragmentController.createController(new RemoteFragmentHostCallback(this));
+
+        // Some appcompat functionality depends on Fragments being hosted from within an
+        // AppCompatActivity, which performs some static initialization. Even if we're running
+        // within an AppCompatActivity, it will be from the embedder's ClassLoader, so in WebLayer's
+        // ClassLoader the initialization hasn't occurred. Creating an AppCompatDelegate manually
+        // here will perform the necessary initialization.
+        AppCompatDelegate.create(getActivity(), null);
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        StrictModeWorkaround.apply();
+        mFragmentController.attachHost(null);
+
+        super.onCreate(savedInstanceState);
+
+        mFragmentController.dispatchCreate();
+    }
+
+    @Override
+    public void onDestroyView() {
+        StrictModeWorkaround.apply();
+        super.onDestroyView();
+        mFragmentController.dispatchDestroyView();
+    }
+
+    @Override
+    public void onDestroy() {
+        StrictModeWorkaround.apply();
+        super.onDestroy();
+        mFragmentController.dispatchDestroy();
+    }
+
+    @Override
+    public void onDetach() {
+        StrictModeWorkaround.apply();
+        super.onDetach();
+        mContext = null;
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+
+        if (!mStarted) {
+            mStarted = true;
+            mFragmentController.dispatchActivityCreated();
+        }
+        mFragmentController.noteStateNotSaved();
+        mFragmentController.execPendingActions();
+        mFragmentController.dispatchStart();
+    }
+
+    @Override
+    public void onStop() {
+        super.onStop();
+        mFragmentController.dispatchStop();
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        mFragmentController.dispatchResume();
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        mFragmentController.dispatchPause();
+    }
+
+    public FragmentManager getSupportFragmentManager() {
+        return mFragmentController.getSupportFragmentManager();
+    }
+
+    /**
+     * Returns the RemoteFragmentContext that should be used in the child Fragment tree.
+     *
+     * Implementations will typically wrap embedderContext with ClassLoaderContextWrapperFactory,
+     * and possibly set a Theme.
+     */
+    protected abstract RemoteFragmentContext createRemoteFragmentContext(Context embedderContext);
+
+    protected Context getWebLayerContext() {
+        return mContext;
+    }
+}