Prompt user to enable chosen WebView provider if disabled.

The WebView loading logic will not allow for the user to pick a provider
that is disabled. But in the WebView developer setting for choosing
provider disabled WebView providers are shown. Therefore if the user
wants to use a disabled provider we (with this patch) prompt them to
enable the provider (if they agree we then enable it).

Bug: 26400585

Change-Id: I42476acc54f01cf873b267dd22079c5c50fa07a2

src/com/android/settings/DevelopmentSettings.java

@@ -23,6 +23,7 @@ import android.app.AlertDialog;
 import android.app.AppOpsManager;
 import android.app.AppOpsManager.PackageOps;
 import android.app.Dialog;
+import android.app.DialogFragment;
 import android.app.UiModeManager;
 import android.app.admin.DevicePolicyManager;
 import android.app.backup.IBackupManager;
@@ -1863,6 +1864,38 @@ public class DevelopmentSettings extends SettingsPreferenceFragment
                 requestCode, resources.getString(R.string.oem_unlock_enable));
     }
 
+    private boolean isPackageEnabled(String packageName) {
+        try {
+            PackageManager pm = getActivity().getPackageManager();
+            int enabled_state = pm.getApplicationEnabledSetting(packageName);
+            switch (enabled_state) {
+                case PackageManager.COMPONENT_ENABLED_STATE_ENABLED:
+                    return true;
+                case PackageManager.COMPONENT_ENABLED_STATE_DEFAULT:
+                    return pm.getPackageInfo(packageName, 0).applicationInfo.enabled;
+                default:
+                    return false;
+            }
+        } catch (NameNotFoundException e) {
+            // Thrown by PackageManager.getPackageInfo if the package does not exist
+        } catch (IllegalArgumentException e) {
+            // Thrown by PackageManager.getApplicationEnabledSetting if the package does not exist
+        }
+        return false;
+    }
+
+    private void enableAndSetWebViewPackage(String packageName) {
+        getActivity().getPackageManager().setApplicationEnabledSetting(packageName,
+                PackageManager.COMPONENT_ENABLED_STATE_ENABLED, 0);
+        mWebViewProvider.setValue(packageName);
+        writeWebViewProviderOptions(packageName);
+    }
+
+    private void showEnableWebViewProviderAlert(final String packageName) {
+        EnableWebViewProviderDialogFragment.newInstance(packageName).show(
+                getChildFragmentManager(), EnableWebViewProviderDialogFragment.TAG);
+    }
+
     @Override
     public boolean onPreferenceChange(Preference preference, Object newValue) {
         if (HDCP_CHECKING_KEY.equals(preference.getKey())) {
@@ -1871,8 +1904,24 @@ public class DevelopmentSettings extends SettingsPreferenceFragment
             pokeSystemProperties();
             return true;
         } else if (preference == mWebViewProvider) {
-            writeWebViewProviderOptions(newValue);
-            return true;
+            if (newValue == null) {
+                Log.e(TAG, "Tried to set a null WebView provider");
+                return false;
+            }
+            String newWebViewPackageName = (String) newValue;
+            if (isPackageEnabled(newWebViewPackageName)) {
+                writeWebViewProviderOptions(newValue);
+                return true;
+            }
+            // Package is disabled or uninstalled, if it is simply disabled, check if the user wants
+            // to enable it
+            if (isPackageInstalled(getActivity(), newWebViewPackageName)) {
+                showEnableWebViewProviderAlert(newWebViewPackageName);
+                return false;
+            }
+            // Package has been uninstalled (could happen if the package was uninstalled between
+            // opening and closing the setting).
+            return false;
         } else if (preference == mLogdSize) {
             writeLogdSizeOption(newValue);
             return true;
@@ -2030,6 +2079,37 @@ public class DevelopmentSettings extends SettingsPreferenceFragment
         }
     }
 
+    public static class EnableWebViewProviderDialogFragment extends DialogFragment {
+        public static final String TAG = "EnableWebViewProviderDialogFragment";
+        private static final String PACKAGE_NAME_TAG = "packageName";
+
+        public static EnableWebViewProviderDialogFragment newInstance(String packageName) {
+            EnableWebViewProviderDialogFragment fragment
+                = new EnableWebViewProviderDialogFragment();
+            Bundle args = new Bundle();
+            args.putString(PACKAGE_NAME_TAG, packageName);
+            fragment.setArguments(args);
+            return fragment;
+        }
+
+        @Override
+        public Dialog onCreateDialog(Bundle savedInstanceState) {
+            final String packageName = getArguments().getString(PACKAGE_NAME_TAG);
+
+            return new AlertDialog.Builder(getActivity())
+                .setMessage(R.string.select_webview_provider_confirmation_text)
+                .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                    public void onClick(DialogInterface dialog, int id) {
+                        ((DevelopmentSettings)getParentFragment()).enableAndSetWebViewPackage(
+                            packageName);
+                    }
+                })
+                .setNegativeButton(android.R.string.cancel, null)
+                .create();
+        }
+    }
+
+
     /**
      * For Search.
      */