Show and hide WebView developer UI launcher icon in runtime

Schedule a low priority (best effort) non-blocking PostTask when chrome
comes to the foreground or when a WebView MonoChrome process is created.
The task is responsible to show a launcher icon to open WebView DevTools
if monochrome is the current selected system webview provider otherwise
it hides the launcher icon.

The component (activity-alias) that shows the icon is disabled by
default and is only added to the manifest in build-time when GN argument
`webview_devui_show_icon=true` which is enabled by default for dev and
canary channels.

icon_webview is added to the activity-alias for monochrome so the
launcher icon for DevTools will be WebView icon not Monochrome. However, the icon the
application switcher will still show monochrome icon.

Bug: 1026062
Bug: 1026060
Test: select monochrome as webview implementation and launch monochrome browser, observe icon appearing
Test: select monochrome as webview implementation and launch webview shell browser, observe icon appearing
Test: select different webview implementation, launch monochrome and observe icon disappearing
Change-Id: I9c05aa9d8bcdddc016a06b62a5e76e2aa20f30a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2000724
Commit-Queue: Hazem Ashmawy <hazems@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733974}

android_webview/nonembedded/BUILD.gn

@@ -127,6 +127,7 @@ android_resources("devui_launcher_icon_resources") {
 android_resources("monochrome_devui_launcher_icon_resources") {
   resource_dirs = []
   android_manifest = "java/MonochromeDeveloperUiLauncherManifest.xml"
+  deps = [ ":icon_resources" ]
   custom_package = "org.chromium.android_webview.devui.icon"
 }
 

android_webview/nonembedded/java/MonochromeDeveloperUiLauncherManifest.xml

@@ -14,6 +14,7 @@
         <activity-alias android:name="org.chromium.android_webview.devui.MonochromeLauncherActivity"
                   android:targetActivity="org.chromium.android_webview.devui.MainActivity"
                   android:label="WebView DevTools"
+                  android:icon="@drawable/icon_webview"
                   android:exported="true"
                   android:enabled="false">
             <intent-filter>

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

@@ -120,6 +120,18 @@ public final class WebViewPackageHelper {
         }
     }
 
+    /**
+     * Check if the given context is a WebView package and if it's currently selected as system's
+     * WebView implementation.
+     *
+     * @param context the {@link Context} to check its package.
+     */
+    public static boolean isCurrentSystemWebViewImplementation(Context context) {
+        PackageInfo systemWebViewPackage = getCurrentWebViewPackage(context);
+        if (systemWebViewPackage == null) return false;
+        return context.getPackageName().equals(systemWebViewPackage.packageName);
+    }
+
     // Do not instantiate this class.
     private WebViewPackageHelper() {}
 }

android_webview/nonembedded/java/src/org/chromium/android_webview/nonembedded/WebViewApkApplication.java

@@ -5,16 +5,21 @@
 package org.chromium.android_webview.nonembedded;
 
 import android.app.Application;
+import android.content.ComponentName;
 import android.content.Context;
+import android.content.pm.PackageManager;
 
 import org.chromium.android_webview.AwLocaleConfig;
 import org.chromium.android_webview.common.CommandLineUtil;
+import org.chromium.android_webview.devui.util.WebViewPackageHelper;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.PathUtils;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.NativeMethods;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.base.library_loader.LibraryProcessType;
+import org.chromium.base.task.PostTask;
+import org.chromium.base.task.TaskTraits;
 import org.chromium.components.embedder_support.application.FontPreloadingWorkaround;
 import org.chromium.ui.base.ResourceBundle;
 
@@ -69,6 +74,40 @@ public class WebViewApkApplication extends Application {
         return ContextUtils.getProcessName().contains(":webview_");
     }
 
+    /**
+     * Post a non-blocking, low priority background task that shows a launcher icon for WebView
+     * DevTools if this Monochrome package is the current selected WebView provider for the system
+     * otherwise it hides that icon. This works only for Monochrome and shouldn't be used for other
+     * WebView providers. Other WebView Providers (Standalone and Trichrome) will always have
+     * launcher icons whether they are the current selected providers or not.
+     *
+     * Should be guarded by process type checks and should only be called if it's a webview process
+     * or a browser process.
+     */
+    public static void postDeveloperUiLauncherIconTask() {
+        PostTask.postTask(TaskTraits.BEST_EFFORT, () -> {
+            Context context = ContextUtils.getApplicationContext();
+            try {
+                ComponentName devToolsLauncherActivity = new ComponentName(
+                        context, "org.chromium.android_webview.devui.MonochromeLauncherActivity");
+                if (WebViewPackageHelper.isCurrentSystemWebViewImplementation(context)) {
+                    // Enable the component to show the launcher icon.
+                    context.getPackageManager().setComponentEnabledSetting(devToolsLauncherActivity,
+                            PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
+                            PackageManager.DONT_KILL_APP);
+                } else {
+                    // Disable the component to hide the launcher icon.
+                    context.getPackageManager().setComponentEnabledSetting(devToolsLauncherActivity,
+                            PackageManager.COMPONENT_ENABLED_STATE_DEFAULT,
+                            PackageManager.DONT_KILL_APP);
+                }
+            } catch (IllegalArgumentException e) {
+                // If MonochromeLauncherActivity doesn't exist, Dynamically showing/hiding DevTools
+                // launcher icon is not enabled in this package; e.g when it is a stable channel.
+            }
+        });
+    }
+
     /**
      * Performs minimal native library initialization required when running as a stand-alone APK.
      * @return True if the library was loaded, false if running as webview stub.

android_webview/variables.gni

@@ -7,7 +7,8 @@ import("//weblayer/variables.gni")
 
 declare_args() {
   # Show a launcher icon to open WebView developer UI, enabled by default for dev and canary
-  # channels. The icon for Monochrome is always hidden by default (https://crbug.com/1026062)
+  # channels. The icon for Monochrome is shown dynamically at runtime if Monochrome is the current
+  # selected system WebView implementation or hidden otherwise.
   # TODO(https://crbug.com/1002589): add beta channel when approved
   webview_devui_show_icon =
       android_channel == "canary" || android_channel == "dev"

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

@@ -180,7 +180,7 @@ public class ChromeApplication extends Application {
         return FeatureUtilities.isCommandLineOnNonRootedEnabled();
     }
 
-    private static boolean isBrowserProcess() {
+    protected static boolean isBrowserProcess() {
         return !ContextUtils.getProcessName().contains(":");
     }
 

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

@@ -9,6 +9,8 @@ import android.content.Context;
 import com.android.webview.chromium.MonochromeLibraryPreloader;
 
 import org.chromium.android_webview.nonembedded.WebViewApkApplication;
+import org.chromium.base.ActivityState;
+import org.chromium.base.ApplicationStatus;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.base.library_loader.LibraryProcessType;
 import org.chromium.content_public.browser.ChildProcessCreationParams;
@@ -44,6 +46,31 @@ public class MonochromeApplication extends ChromeApplication {
                 LibraryProcessType.PROCESS_CHILD, bindToCaller, ignoreVisibilityForImportance);
     }
 
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        // TODO(https://crbug.com/1002589): remove beta channel check when approved
+        if (!ChromeVersionInfo.isStableBuild() && !ChromeVersionInfo.isBetaBuild()) {
+            // Performing Monochrome WebView DevTools Launcher icon showing/hiding logic in onCreate
+            // rather than in attachBaseContext() because it depends on application context being
+            // initiatied.
+            if (isWebViewProcess()) {
+                // Whenever a monochrome webview process is launched (WebView service or developer
+                // UI), post a background task to show/hide the DevTools icon.
+                WebViewApkApplication.postDeveloperUiLauncherIconTask();
+            } else if (isBrowserProcess()) {
+                // Frequently check current system webview provider and show/hide the icon
+                // accordingly by listening to Monochrome browser Activities status (whenever a
+                // browser activity comes to the foreground).
+                ApplicationStatus.registerStateListenerForAllActivities((activity, state) -> {
+                    if (state == ActivityState.RESUMED) {
+                        WebViewApkApplication.postDeveloperUiLauncherIconTask();
+                    }
+                });
+            }
+        }
+    }
+
     @Override
     protected boolean isWebViewProcess() {
         return WebViewApkApplication.isWebViewProcess();