[AW] Dev UI: Show error if system uses different WebView impl

Show a persistent error message at the top of the activities as well as
a dialogue when the activity is launched, to warn the user that they are
using a developer UI from a package that is different from the WebView
package selected by the system.

Bug: 981150
Test: Launch Dev UI from Trichrome, change webview implementation and switch back to the UI.
Change-Id: If3ec3f09f4d8e1632583f3448d2d6e4bbf841607
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1912119
Commit-Queue: Hazem Ashmawy <hazems@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715958}

android_webview/nonembedded/BUILD.gn

@@ -39,12 +39,15 @@ android_library("devui_java") {
     "java/src/org/chromium/android_webview/devui/CrashesListActivity.java",
     "java/src/org/chromium/android_webview/devui/FlagsActivity.java",
     "java/src/org/chromium/android_webview/devui/MainActivity.java",
+    "java/src/org/chromium/android_webview/devui/PersistentErrorView.java",
+    "java/src/org/chromium/android_webview/devui/WebViewPackageError.java",
     "java/src/org/chromium/android_webview/devui/util/CrashInfoLoader.java",
     "java/src/org/chromium/android_webview/devui/util/NavigationMenuHelper.java",
     "java/src/org/chromium/android_webview/devui/util/UnuploadedFilesStateLoader.java",
     "java/src/org/chromium/android_webview/devui/util/UploadedCrashesInfoLoader.java",
     "java/src/org/chromium/android_webview/devui/util/WebViewCrashInfoCollector.java",
     "java/src/org/chromium/android_webview/devui/util/WebViewCrashLogParser.java",
+    "java/src/org/chromium/android_webview/devui/util/WebViewPackageHelper.java",
   ]
   deps = [
     ":devui_resources",

android_webview/nonembedded/java/res_devui/layout/activity_crashes_list.xml

@@ -7,6 +7,7 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/crashes_list_activity_layout"
     android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent">

android_webview/nonembedded/java/res_devui/layout/activity_flags.xml

@@ -7,7 +7,7 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/activity_flags"
+    android:id="@+id/flags_activity_layout"
     android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
@@ -17,7 +17,7 @@
     <TextView
         android:id="@+id/flags_warning"
         android:text="WARNING: EXPERIMENTAL FEATURES AHEAD!"
-        android:textColor="@color/warningText"
+        android:textColor="@color/error_red"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingBottom="5dp"

android_webview/nonembedded/java/res_devui/layout/activity_main.xml

@@ -7,6 +7,7 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/main_activity_layout"
     android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent">

android_webview/nonembedded/java/res_devui/layout/persistent_error_message.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2019 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.
+-->
+
+<TextView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:textAppearance="?android:attr/textAppearanceMedium"
+    android:textStyle="italic"
+    android:drawableStart="@android:drawable/stat_notify_error"
+    android:drawablePadding="8dp"
+    android:paddingTop="20dp"
+    android:paddingBottom="20dp"
+    android:paddingStart="?android:attr/listPreferredItemPaddingStart"
+    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"/>

android_webview/nonembedded/java/res_devui/values/colors.xml

@@ -6,5 +6,6 @@
 -->
 
 <resources>
-    <color name="warningText">#C5221F</color>
+    <color name="error_red">#C5221F</color>
+    <color name="warning_yellow">#FFCC00</color>
 </resources>

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/CrashesListActivity.java

@@ -41,8 +41,9 @@ public class CrashesListActivity extends Activity {
 
     private TextView mCrashesSummaryView;
     private BaseExpandableListAdapter mCrashListViewAdapter;
-    private WebViewCrashInfoCollector mCrashCollector;
+    private WebViewPackageError mDifferentPackageError;
 
+    private WebViewCrashInfoCollector mCrashCollector;
     private List<CrashInfo> mCrashInfoList;
 
     private static final String CRASH_REPORT_TEMPLATE = ""
@@ -91,6 +92,20 @@ public class CrashesListActivity extends Activity {
 
         ExpandableListView crashListView = findViewById(R.id.crashes_list);
         crashListView.setAdapter(mCrashListViewAdapter);
+
+        mDifferentPackageError =
+                new WebViewPackageError(this, findViewById(R.id.crashes_list_activity_layout));
+        // show the dialog once when the activity is created.
+        mDifferentPackageError.showDialogIfDifferent();
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        // Check package status in onResume() to hide/show the error message if the user
+        // changes WebView implementation from system settings and then returns back to the
+        // activity.
+        mDifferentPackageError.showMessageIfDifferent();
     }
 
     /**

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/FlagsActivity.java

@@ -42,6 +42,8 @@ public class FlagsActivity extends Activity {
             "Disabled",
     };
 
+    private WebViewPackageError mDifferentPackageError;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -56,6 +58,20 @@ public class FlagsActivity extends Activity {
 
         List<Flag> flagsList = Arrays.asList(ProductionSupportedFlagList.sFlagList);
         flagsListView.setAdapter(new FlagsListAdapter(flagsList));
+
+        mDifferentPackageError =
+                new WebViewPackageError(this, findViewById(R.id.flags_activity_layout));
+        // show the dialog once when the activity is created.
+        mDifferentPackageError.showDialogIfDifferent();
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        // Check package status in onResume() to hide/show the error message if the user
+        // changes WebView implementation from system settings and then returns back to the
+        // activity.
+        mDifferentPackageError.showMessageIfDifferent();
     }
 
     private class FlagStateSpinnerSelectedListener implements AdapterView.OnItemSelectedListener {

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/MainActivity.java

@@ -8,7 +8,6 @@ import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.pm.PackageInfo;
-import android.content.pm.PackageManager.NameNotFoundException;
 import android.os.Build;
 import android.os.Bundle;
 import android.view.Menu;
@@ -20,6 +19,7 @@ import android.widget.ListView;
 import android.widget.TextView;
 
 import org.chromium.android_webview.devui.util.NavigationMenuHelper;
+import org.chromium.android_webview.devui.util.WebViewPackageHelper;
 import org.chromium.ui.widget.Toast;
 
 import java.util.Locale;
@@ -30,19 +30,19 @@ import java.util.Locale;
  * It helps to navigate to other WebView developer tools.
  */
 public class MainActivity extends Activity {
+    private WebViewPackageError mDifferentPackageError;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_main);
 
-        PackageInfo webViewPackage = getPackageInfo();
+        PackageInfo webViewPackage = WebViewPackageHelper.getContextPackageInfo(this);
         InfoItem[] infoItems = new InfoItem[] {
-                new InfoItem("WebView package",
-                        webViewPackage == null ? null : webViewPackage.packageName),
+                new InfoItem("WebView package", webViewPackage.packageName),
                 new InfoItem("WebView version",
-                        String.format(Locale.US, "%s (%s)",
-                                webViewPackage == null ? null : webViewPackage.versionName,
+                        String.format(Locale.US, "%s (%s)", webViewPackage.versionName,
                                 webViewPackage.versionCode)),
                 new InfoItem("Device info",
                         String.format(Locale.US, "%s - %s", Build.MODEL, Build.FINGERPRINT)),
@@ -62,6 +62,20 @@ public class MainActivity extends Activity {
             // Show a toast that the text has been copied.
             Toast.makeText(MainActivity.this, "Copied " + item.title, Toast.LENGTH_SHORT).show();
         });
+
+        mDifferentPackageError =
+                new WebViewPackageError(this, findViewById(R.id.main_activity_layout));
+        // show the dialog once when the activity is created.
+        mDifferentPackageError.showDialogIfDifferent();
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        // Check package status in onResume() to hide/show the error message if the user
+        // changes WebView implementation from system settings and then returns back to the
+        // activity.
+        mDifferentPackageError.showMessageIfDifferent();
     }
 
     /**
@@ -125,12 +139,4 @@ public class MainActivity extends Activity {
         }
         return super.onOptionsItemSelected(item);
     }
-
-    private PackageInfo getPackageInfo() {
-        try {
-            return getPackageManager().getPackageInfo(getPackageName(), 0);
-        } catch (NameNotFoundException e) {
-            return null;
-        }
-    }
 }

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/PersistentErrorView.java

+// Copyright 2019 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.android_webview.devui;
+
+import android.app.Activity;
+import android.app.Dialog;
+import android.graphics.Color;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+/**
+ * Shows a text message at the top of a LinearLayout to show error and warning messages.
+ */
+public class PersistentErrorView {
+    /**
+     * Error message type.
+     */
+    public enum Type {
+        ERROR,
+        WARNING,
+    }
+
+    private TextView mTextView;
+
+    /**
+     * @param context The Activity where this View is shon.
+     * @param type View type.
+     */
+    public PersistentErrorView(Activity context, Type type) {
+        mTextView = (TextView) context.getLayoutInflater().inflate(
+                R.layout.persistent_error_message, null);
+
+        switch (type) {
+            case ERROR:
+                mTextView.setBackgroundResource(R.color.error_red);
+                mTextView.setTextColor(Color.WHITE);
+                break;
+            case WARNING:
+                mTextView.setBackgroundResource(R.color.warning_yellow);
+                mTextView.setTextColor(Color.BLACK);
+                break;
+        }
+    }
+
+    /**
+     * Add the error message view at the top of the given {@link LinearLayout}
+     * @param layout the linear layout to add this view at the top.
+     * @return object reference for chaining.
+     */
+    public PersistentErrorView prependToLinearLayout(LinearLayout layout) {
+        layout.addView(mTextView, 0);
+        return this;
+    }
+
+    /**
+     * Set click event listener of this view.
+     * @param listener listener object to handle the click event.
+     * @return object reference for chaining.
+     */
+    public PersistentErrorView setOnClickListener(OnClickListener listener) {
+        mTextView.setOnClickListener(listener);
+        return this;
+    }
+
+    /**
+     * Set a dialog to show when the view is clicked.
+     * @param dialog {@link Dialog} object to to show when the view is clicked.
+     * @return object reference for chaining.
+     */
+    public PersistentErrorView setDialog(Dialog dialog) {
+        setOnClickListener(v -> dialog.show());
+        return this;
+    }
+
+    /**
+     * Set view text.
+     * @param text text {@link String} to show in the error View.
+     * @return object reference for chaining.
+     */
+    public PersistentErrorView setText(String text) {
+        mTextView.setText(text);
+        return this;
+    }
+
+    /**
+     * Show the view by setting its visibility.
+     */
+    public void show() {
+        mTextView.setVisibility(View.VISIBLE);
+    }
+
+    /**
+     * Hide the view by setting its visibility.
+     */
+    public void hide() {
+        mTextView.setVisibility(View.GONE);
+    }
+}

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/WebViewPackageError.java

+// Copyright 2019 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.android_webview.devui;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.Intent;
+import android.content.pm.PackageInfo;
+import android.content.pm.ResolveInfo;
+import android.provider.Settings;
+import android.widget.LinearLayout;
+
+import org.chromium.android_webview.devui.util.WebViewPackageHelper;
+import org.chromium.base.Log;
+
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * A helper class to yield an error if the the UI is launched from a different WebView package other
+ * than the selected package by the system. It shows a persistent error message at the top of the
+ * activity's root linear layout as well as an alert dialogue to change WebView implementation.
+ */
+public class WebViewPackageError {
+    private static final String TAG = "WebViewDevTools";
+
+    private PersistentErrorView mErrorMessage;
+    private Activity mContext;
+    private Dialog mErrorDialog;
+
+    /**
+     * @param context The {@link Activity} where the error is yield.
+     * @param linearLayout the linearLayout to show error message at it's top.
+     */
+    public WebViewPackageError(Activity context, LinearLayout linearLayout) {
+        mContext = context;
+
+        mErrorDialog = buildDifferentPackageErrorDialog(mContext.getPackageName());
+        mErrorMessage = new PersistentErrorView(context, PersistentErrorView.Type.WARNING)
+                                .prependToLinearLayout(linearLayout)
+                                .setText("Warning: different WebView provider - Tap for more info.")
+                                .setDialog(mErrorDialog);
+    }
+
+    /**
+     * Show the persistent error message at the top of the LinearLayout, if the system uses a
+     * different WebView implementation. Hide it otherwise.
+     */
+    public void showMessageIfDifferent() {
+        if (isWebViewPackageDifferent()) {
+            mErrorMessage.show();
+        } else {
+            mErrorMessage.hide();
+        }
+    }
+
+    /**
+     * Show an {@link AlertDialog} about the different WebView package error with an action to
+     * launch system settings to show and change WebView implementation.
+     */
+    public void showDialogIfDifferent() {
+        if (isWebViewPackageDifferent()) {
+            mErrorDialog.show();
+        }
+    }
+
+    private boolean isWebViewPackageDifferent() {
+        PackageInfo systemWebViewPackage = WebViewPackageHelper.getCurrentWebViewPackage(mContext);
+        if (systemWebViewPackage == null) {
+            Log.e(TAG, "Could not find a valid WebView implementation");
+            buildNoValidWebViewPackageDialog().show();
+            return true;
+        }
+        return !mContext.getPackageName().equals(systemWebViewPackage.packageName);
+    }
+
+    private Dialog buildDifferentPackageErrorDialog(String currentWebViewPackage) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
+        builder.setTitle("Wrong WebView DevTools")
+                .setMessage(String.format(Locale.US,
+                        "This app (%s) is not the selected system's WebView provider.",
+                        currentWebViewPackage));
+        builder.setPositiveButton("Open the current WebView provider", (dialog, id) -> {
+            PackageInfo systemWebViewPackage =
+                    WebViewPackageHelper.getCurrentWebViewPackage(mContext);
+            if (systemWebViewPackage == null) {
+                Log.e(TAG, "Could not find a valid WebView implementation");
+                buildNoValidWebViewPackageDialog().show();
+                return;
+            }
+            Intent intent = new Intent("com.android.webview.SHOW_DEV_UI");
+            intent.setPackage(systemWebViewPackage.packageName);
+            // Check if the intent is resolved, i.e current system WebView package has a developer
+            // UI that responds to "com.android.webview.SHOW_DEV_UI" action.
+            List<ResolveInfo> resolveInfo =
+                    mContext.getPackageManager().queryIntentActivities(intent, 0);
+            if (resolveInfo.isEmpty()) {
+                buildNoDevToolsDialog(systemWebViewPackage.packageName).show();
+                return;
+            }
+            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+            mContext.startActivity(intent);
+            mContext.finishAndRemoveTask();
+        });
+
+        builder.setNeutralButton("Change WebView provider",
+                (dialog, id)
+                        -> mContext.startActivity(new Intent(Settings.ACTION_WEBVIEW_SETTINGS)));
+
+        return builder.create();
+    }
+
+    private Dialog buildNoValidWebViewPackageDialog() {
+        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
+        builder.setTitle("No Valid WebView")
+                .setMessage("Cannot find a valid WebView provider installed. "
+                        + "Please install a valid WebView package. Contact "
+                        + "android-webview-dev@chromium.org for help.");
+
+        return builder.create();
+    }
+
+    private Dialog buildNoDevToolsDialog(String sytemWebViewPackageName) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
+        builder.setTitle("DevTools Not Found")
+                .setMessage(String.format(Locale.US,
+                        "DevTools are not available in the current "
+                                + "WebView provider selected by the system (%s).\n\n"
+                                + "Please update to a newer version or select a different WebView "
+                                + "provider.",
+                        sytemWebViewPackageName));
+        builder.setPositiveButton("Change WebView provider",
+                (dialog, id)
+                        -> mContext.startActivity(new Intent(Settings.ACTION_WEBVIEW_SETTINGS)));
+
+        return builder.create();
+    }
+}

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/util/WebViewPackageHelper.java

+// Copyright 2019 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.android_webview.devui.util;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.webkit.WebView;
+
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ * A helper class to get info about WebView package.
+ */
+public final class WebViewPackageHelper {
+    /**
+     * If WebView has already been loaded into the current process this method will return the
+     * package that was used to load it. Otherwise, the package that would be used if the WebView
+     * was loaded right now will be returned; this does not cause WebView to be loaded, so this
+     * information may become outdated at any time.
+     * The WebView package changes either when the current WebView package is updated, disabled, or
+     * uninstalled. It can also be changed through a Developer Setting.
+     * If the WebView package changes, any app process that has loaded WebView will be killed. The
+     * next time the app starts and loads WebView it will use the new WebView package instead.
+     * @return the current WebView package, or {@code null} if there is none.
+     */
+    // This method is copied from androidx.webkit.WebViewCompat.
+    // TODO(crbug.com/1020024) use androidx.webkit.WebViewCompat#getCurrentWebViewPackage instead.
+    public static PackageInfo getCurrentWebViewPackage(Context context) {
+        // There was no WebView Package before Lollipop, the WebView code was part of the framework
+        // back then.
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return null;
+        }
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            return WebView.getCurrentWebViewPackage();
+        } else { // L-N
+            try {
+                PackageInfo loadedWebViewPackageInfo = getLoadedWebViewPackageInfo();
+                if (loadedWebViewPackageInfo != null) return loadedWebViewPackageInfo;
+            } catch (ClassNotFoundException | IllegalAccessException | InvocationTargetException
+                    | NoSuchMethodException e) {
+                return null;
+            }
+
+            // If WebViewFactory.getLoadedPackageInfo() returns null then WebView hasn't been loaded
+            // yet, in that case we need to fetch the name of the WebView package, and fetch the
+            // corresponding PackageInfo through the PackageManager
+            return getNotYetLoadedWebViewPackageInfo(context);
+        }
+    }
+
+    /**
+     * Return the PackageInfo of the currently loaded WebView APK. This method uses reflection and
+     * propagates any exceptions thrown, to the caller.
+     */
+    // This method is copied from androidx.webkit.WebViewCompat.
+    @SuppressLint("PrivateApi")
+    private static PackageInfo getLoadedWebViewPackageInfo()
+            throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException,
+                   IllegalAccessException {
+        Class<?> webViewFactoryClass = Class.forName("android.webkit.WebViewFactory");
+        return (PackageInfo) webViewFactoryClass.getMethod("getLoadedPackageInfo").invoke(null);
+    }
+
+    /**
+     * Return the PackageInfo of the WebView APK that would have been used as WebView implementation
+     * if WebView was to be loaded right now.
+     */
+    // This method is copied from androidx.webkit.WebViewCompat.
+    @SuppressLint("PrivateApi")
+    private static PackageInfo getNotYetLoadedWebViewPackageInfo(Context context) {
+        String webviewPackageName;
+        try {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP
+                    && Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
+                Class<?> webViewFactoryClass = Class.forName("android.webkit.WebViewFactory");
+
+                webviewPackageName = (String) webViewFactoryClass.getMethod("getWebViewPackageName")
+                                             .invoke(null);
+            } else {
+                Class<?> webviewUpdateServiceClass =
+                        Class.forName("android.webkit.WebViewUpdateService");
+                webviewPackageName =
+                        (String) webviewUpdateServiceClass.getMethod("getCurrentWebViewPackageName")
+                                .invoke(null);
+            }
+        } catch (ClassNotFoundException e) {
+            return null;
+        } catch (IllegalAccessException e) {
+            return null;
+        } catch (InvocationTargetException e) {
+            return null;
+        } catch (NoSuchMethodException e) {
+            return null;
+        }
+        if (webviewPackageName == null) return null;
+        PackageManager pm = context.getPackageManager();
+        try {
+            return pm.getPackageInfo(webviewPackageName, 0);
+        } catch (PackageManager.NameNotFoundException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Get {@link PackageInfo} for the given {@link Context}.
+     * It uses {@link Context#getPackageName()} to look up the {@link PackageInfo} object.
+     */
+    public static PackageInfo getContextPackageInfo(Context context) {
+        try {
+            return context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
+        } catch (PackageManager.NameNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    // Do not instantiate this class.
+    private WebViewPackageHelper() {}
+}