Add support for only enabling QR scanner in QS tile

This CL adds a config to control enabling/disabling of just the
lockscreen button for QR code scanner

Bug: 200536509
Test: Manually
Change-Id: I9850994d9c53446d82506369e5069eea6eceb6da

core/api/system-current.txt

@@ -366,6 +366,7 @@ package android {
   }
 
   public static final class R.bool {
+    field public static final int config_enableQrCodeScannerOnLockScreen;
     field public static final int config_sendPackageName = 17891328; // 0x1110000
     field public static final int config_showDefaultAssistant = 17891329; // 0x1110001
     field public static final int config_showDefaultEmergency = 17891330; // 0x1110002

core/res/res/values/config.xml

@@ -5607,4 +5607,7 @@
 
     <!-- Flag indicating if help links for Settings app should be enabled. -->
     <bool name="config_settingsHelpLinksEnabled">false</bool>
+
+    <!-- Whether or not to enable the lock screen entry point for the QR code scanner. -->
+    <bool name="config_enableQrCodeScannerOnLockScreen">false</bool>
 </resources>

core/res/res/values/public.xml

@@ -3322,6 +3322,8 @@
   <staging-public-group type="bool" first-id="0x01cf0000">
     <!-- @hide @TestApi -->
     <public name="config_preventImeStartupUnlessTextEditor" />
+    <!-- @hide @SystemApi -->
+    <public name="config_enableQrCodeScannerOnLockScreen" />
   </staging-public-group>
 
   <staging-public-group type="fraction" first-id="0x01ce0000">

packages/SystemUI/src/com/android/systemui/qrcodescanner/controller/QRCodeScannerController.java

@@ -93,6 +93,7 @@ public class QRCodeScannerController implements
     private final DeviceConfigProxy mDeviceConfigProxy;
     private final ArrayList<Callback> mCallbacks = new ArrayList<>();
     private final UserTracker mUserTracker;
+    private final boolean mConfigEnableLockScreenButton;
 
     private HashMap<Integer, ContentObserver> mQRCodeScannerPreferenceObserver = new HashMap<>();
     private DeviceConfig.OnPropertiesChangedListener mOnDefaultQRCodeScannerChangedListener = null;
@@ -118,6 +119,9 @@ public class QRCodeScannerController implements
         mSecureSettings = secureSettings;
         mDeviceConfigProxy = proxy;
         mUserTracker = userTracker;
+
+        mConfigEnableLockScreenButton = mContext.getResources().getBoolean(
+            android.R.bool.config_enableQrCodeScannerOnLockScreen);
     }
 
     /**
@@ -156,7 +160,7 @@ public class QRCodeScannerController implements
      * Returns true if lock screen entry point for QR Code Scanner is to be enabled.
      */
     public boolean isEnabledForLockScreenButton() {
-        return mQRCodeScannerEnabled && mIntent != null;
+        return mQRCodeScannerEnabled && mIntent != null && mConfigEnableLockScreenButton;
     }
 
     /**
@@ -235,6 +239,11 @@ public class QRCodeScannerController implements
     }
 
     private void updateQRCodeScannerPreferenceDetails(boolean updateSettings) {
+        if (!mConfigEnableLockScreenButton) {
+            // Settings only apply to lock screen entry point.
+            return;
+        }
+
         boolean prevQRCodeScannerEnabled = mQRCodeScannerEnabled;
         mQRCodeScannerEnabled = mSecureSettings.getIntForUser(LOCK_SCREEN_SHOW_QR_CODE_SCANNER, 0,
                 mUserTracker.getUserId()) != 0;
@@ -251,8 +260,15 @@ public class QRCodeScannerController implements
     private void updateQRCodeScannerActivityDetails() {
         String qrCodeScannerActivity = mDeviceConfigProxy.getString(
                 DeviceConfig.NAMESPACE_SYSTEMUI,
-                SystemUiDeviceConfigFlags.DEFAULT_QR_CODE_SCANNER,
-                mContext.getResources().getString(R.string.def_qr_code_component));
+                SystemUiDeviceConfigFlags.DEFAULT_QR_CODE_SCANNER, "");
+
+        // "" means either the flags is not available or is set to "", and in both the cases we
+        // want to use R.string.def_qr_code_component
+        if (Objects.equals(qrCodeScannerActivity, "")) {
+            qrCodeScannerActivity =
+                    mContext.getResources().getString(R.string.def_qr_code_component);
+        }
+
         String prevQrCodeScannerActivity = mQRCodeScannerActivity;
         ComponentName componentName = null;
         Intent intent = new Intent();
@@ -296,6 +312,11 @@ public class QRCodeScannerController implements
     }
 
     private void unregisterQRCodePreferenceObserver() {
+        if (!mConfigEnableLockScreenButton) {
+            // Settings only apply to lock screen entry point.
+            return;
+        }
+
         mQRCodeScannerPreferenceObserver.forEach((key, value) -> {
             mSecureSettings.unregisterContentObserver(value);
         });
@@ -357,6 +378,11 @@ public class QRCodeScannerController implements
     }
 
     private void registerQRCodePreferenceObserver() {
+        if (!mConfigEnableLockScreenButton) {
+            // Settings only apply to lock screen entry point.
+            return;
+        }
+
         int userId = mUserTracker.getUserId();
         if (mQRCodeScannerPreferenceObserver.getOrDefault(userId, null) != null) return;