Adding "Install Other Apps" in App Info page

Added a preference link to manage external sources in the app info
screen just like other special access permissions.

Test: Manually checked that the link appears on apps once their app op
is set to allow or deny.
Also, added some basic robolectric unit tests:
make -j32 RunSettingsRoboTests

Bug: 35481942
Change-Id: If687778b7a64fb7d278508b78d06272253a98e3e

src/com/android/settings/applications/AppStateInstallAppsBridge.java

@@ -123,9 +123,8 @@ public class AppStateInstallAppsBridge extends AppStateBaseBridge {
             }
         }
 
-        public int getSummary() {
-            return canInstallApps() ? R.string.external_source_trusted
-                    : R.string.external_source_untrusted;
+        public boolean isPotentialAppSource() {
+            return appOpMode != AppOpsManager.MODE_DEFAULT || permissionRequested;
         }
 
         @Override
@@ -150,7 +149,7 @@ public class AppStateInstallAppsBridge extends AppStateBaseBridge {
                 return false;
             }
             InstallAppsState state = (InstallAppsState) info.extraInfo;
-            return (state.appOpMode != AppOpsManager.MODE_DEFAULT) || state.permissionRequested;
+            return state.isPotentialAppSource();
         }
     };
 }

src/com/android/settings/applications/ExternalSourcesDetails.java

@@ -27,6 +27,7 @@ import android.support.v7.preference.Preference.OnPreferenceChangeListener;
 
 import com.android.settings.R;
 import com.android.settings.applications.AppStateInstallAppsBridge.InstallAppsState;
+import com.android.settingslib.applications.ApplicationsState.AppEntry;
 
 public class ExternalSourcesDetails extends AppInfoWithHeader
         implements OnPreferenceChangeListener {
@@ -74,6 +75,18 @@ public class ExternalSourcesDetails extends AppInfoWithHeader
         return false;
     }
 
+    static CharSequence getPreferenceSummary(Context context, AppEntry entry) {
+        final InstallAppsState appsState;
+        if (entry.extraInfo instanceof InstallAppsState) {
+            appsState = (InstallAppsState) entry.extraInfo;
+        } else {
+            appsState = new AppStateInstallAppsBridge(context, null, null)
+                    .createInstallAppsStateFor(entry.info.packageName, entry.info.uid);
+        }
+        return context.getString(appsState.canInstallApps() ? R.string.external_source_trusted
+                : R.string.external_source_untrusted);
+    }
+
     private void setCanInstallApps(boolean newState) {
         mAppOpsManager.setMode(AppOpsManager.OP_REQUEST_INSTALL_PACKAGES,
                 mPackageInfo.applicationInfo.uid, mPackageName,

src/com/android/settings/applications/InstalledAppDetails.java

@@ -969,7 +969,9 @@ public class InstalledAppDetails extends AppInfoBase
                 PictureInPictureSettings.checkPackageHasPictureInPictureActivities(
                         packageInfoWithActivities.packageName,
                         packageInfoWithActivities.activities);
-        if (hasDrawOverOtherApps || hasWriteSettings || hasPictureInPictureActivities) {
+        boolean isPotentialAppSource = isPotentialAppSource();
+        if (hasDrawOverOtherApps || hasWriteSettings || hasPictureInPictureActivities ||
+                isPotentialAppSource) {
             PreferenceCategory category = new PreferenceCategory(getPrefContext());
             category.setTitle(R.string.advanced_apps);
             screen.addPreference(category);
@@ -1019,11 +1021,32 @@ public class InstalledAppDetails extends AppInfoBase
                 });
                 category.addPreference(pref);
             }
+            if (isPotentialAppSource) {
+                Preference pref = new Preference(getPrefContext());
+                pref.setTitle(R.string.install_other_apps);
+                pref.setKey("install_other_apps");
+                pref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
+                    @Override
+                    public boolean onPreferenceClick(Preference preference) {
+                        startAppInfoFragment(ExternalSourcesDetails.class,
+                                getString(R.string.install_other_apps));
+                        return true;
+                    }
+                });
+                category.addPreference(pref);
+            }
         }
 
         addAppInstallerInfoPref(screen);
     }
 
+    private boolean isPotentialAppSource() {
+        AppStateInstallAppsBridge.InstallAppsState appState =
+                new AppStateInstallAppsBridge(getContext(), null, null)
+                        .createInstallAppsStateFor(mPackageName, mPackageInfo.applicationInfo.uid);
+        return appState.isPotentialAppSource();
+    }
+
     private void addAppInstallerInfoPref(PreferenceScreen screen) {
         String installerPackageName = null;
         try {
@@ -1109,6 +1132,10 @@ public class InstalledAppDetails extends AppInfoBase
         if (pref != null) {
             pref.setSummary(WriteSettingsDetails.getSummary(getContext(), mAppEntry));
         }
+        pref = findPreference("install_other_apps");
+        if (pref != null) {
+            pref.setSummary(ExternalSourcesDetails.getPreferenceSummary(getContext(), mAppEntry));
+        }
     }
 
     public static void setupAppSnippet(View appSnippet, CharSequence label, Drawable icon,

src/com/android/settings/applications/ManageApplications.java

@@ -1373,8 +1373,8 @@ public class ManageApplications extends InstrumentedPreferenceFragment
                     break;
 
                 case LIST_TYPE_MANAGE_SOURCES:
-                    holder.summary
-                            .setText(((InstallAppsState) holder.entry.extraInfo).getSummary());
+                    holder.summary.setText(ExternalSourcesDetails.getPreferenceSummary(mContext,
+                            holder.entry));
                     break;
 
                 default: