Prevent screenshot when admin disable screenshots for all users

* An IT admin has the ability to disable screenshots
  for all users when the device has a DO or COPE PO
* When screenshots are disabled for all users, prevent
  a screenshot from being taken instead of taking a
  black screenshot

Bug: 217558483
Test: Manual testing with TestDPC
Change-Id: I167996bb337cc906b5475089f674fd9c37dff808

packages/SystemUI/res/values/strings.xml

@@ -213,6 +213,8 @@
     <!-- Notification text displayed when we fail to take a screenshot. [CHAR LIMIT=100] -->
     <string name="screenshot_failed_to_capture_text">Taking screenshots isn\'t allowed by the app or
         your organization</string>
+    <!-- Notification text displayed when screenshots are blocked by an IT admin. [CHAR LIMIT=100] -->
+    <string name="screenshot_blocked_by_admin">Taking screenshots is blocked by your IT admin</string>
     <!-- Label for UI element which allows editing the screenshot [CHAR LIMIT=30] -->
     <string name="screenshot_edit_label">Edit</string>
     <!-- Content description indicating that tapping the element will allow editing the screenshot [CHAR LIMIT=NONE] -->

packages/SystemUI/src/com/android/systemui/screenshot/TakeScreenshotService.java

@@ -27,6 +27,7 @@ import static com.android.systemui.screenshot.LogConfig.logTag;
 
 import android.annotation.MainThread;
 import android.app.Service;
+import android.app.admin.DevicePolicyManager;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
@@ -42,9 +43,11 @@ import android.os.Looper;
 import android.os.Message;
 import android.os.Messenger;
 import android.os.RemoteException;
+import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Log;
 import android.view.WindowManager;
+import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 
@@ -62,9 +65,11 @@ public class TakeScreenshotService extends Service {
     private ScreenshotController mScreenshot;
 
     private final UserManager mUserManager;
+    private final DevicePolicyManager mDevicePolicyManager;
     private final UiEventLogger mUiEventLogger;
     private final ScreenshotNotificationsController mNotificationsController;
     private final Handler mHandler;
+    private final Context mContext;
 
     private final BroadcastReceiver mCloseSystemDialogs = new BroadcastReceiver() {
         @Override
@@ -91,16 +96,18 @@ public class TakeScreenshotService extends Service {
 
     @Inject
     public TakeScreenshotService(ScreenshotController screenshotController, UserManager userManager,
-            UiEventLogger uiEventLogger,
-            ScreenshotNotificationsController notificationsController) {
+            DevicePolicyManager devicePolicyManager, UiEventLogger uiEventLogger,
+            ScreenshotNotificationsController notificationsController, Context context) {
         if (DEBUG_SERVICE) {
             Log.d(TAG, "new " + this);
         }
         mHandler = new Handler(Looper.getMainLooper(), this::handleMessage);
         mScreenshot = screenshotController;
         mUserManager = userManager;
+        mDevicePolicyManager = devicePolicyManager;
         mUiEventLogger = uiEventLogger;
         mNotificationsController = notificationsController;
+        mContext = context;
     }
 
     @Override
@@ -182,6 +189,14 @@ public class TakeScreenshotService extends Service {
             requestCallback.reportError();
             return true;
         }
+        if(mDevicePolicyManager.getScreenCaptureDisabled(null, UserHandle.USER_ALL)) {
+            Log.w(TAG, "Skipping screenshot because an IT admin has disabled "
+                    + "screenshots on the device");
+            Toast.makeText(mContext, R.string.screenshot_blocked_by_admin,
+                    Toast.LENGTH_SHORT).show();
+            requestCallback.reportError();
+            return true;
+        }
 
         ScreenshotHelper.ScreenshotRequest screenshotRequest =
                 (ScreenshotHelper.ScreenshotRequest) msg.obj;