am adb9554d: Merge "Enable back button in keyguard security account mode." into jb-mr2-dev

* commit 'adb9554d993a8510bfc3866538faaa042d629731':
  Enable back button in keyguard security account mode.

policy/src/com/android/internal/policy/impl/keyguard/KeyguardHostView.java

@@ -310,9 +310,7 @@ public class KeyguardHostView extends KeyguardViewBase {
         mKeyguardSelectorView = (KeyguardSelectorView) findViewById(R.id.keyguard_selector_view);
         mViewStateManager.setSecurityViewContainer(mSecurityViewContainer);
 
-        if (!(mContext instanceof Activity)) {
-            setSystemUiVisibility(getSystemUiVisibility() | View.STATUS_BAR_DISABLE_BACK);
-        }
+        setBackButtonEnabled(false);
 
         addDefaultWidgets();
 
@@ -329,6 +327,13 @@ public class KeyguardHostView extends KeyguardViewBase {
         updateSecurityViews();
     }
 
+    private void setBackButtonEnabled(boolean enabled) {
+        if (mContext instanceof Activity) return;  // always enabled in activity mode
+        setSystemUiVisibility(enabled ?
+                getSystemUiVisibility() & ~View.STATUS_BAR_DISABLE_BACK :
+                getSystemUiVisibility() | View.STATUS_BAR_DISABLE_BACK);
+    }
+
     private boolean shouldEnableAddWidget() {
         return numWidgets() < MAX_WIDGETS && mUserSetupCompleted;
     }
@@ -907,6 +912,10 @@ public class KeyguardHostView extends KeyguardViewBase {
             // Discard current runnable if we're switching back to the selector view
             setOnDismissAction(null);
         }
+        if (securityMode == SecurityMode.Account && !mLockPatternUtils.isPermanentlyLocked()) {
+            // we're showing account as a backup, provide a way to get back to primary
+            setBackButtonEnabled(true);
+        }
         mCurrentSecuritySelection = securityMode;
     }
 
@@ -1579,6 +1588,12 @@ public class KeyguardHostView extends KeyguardViewBase {
     }
 
     public boolean handleBackKey() {
+        if (mCurrentSecuritySelection == SecurityMode.Account) {
+            // go back to primary screen and re-disable back
+            setBackButtonEnabled(false);
+            showPrimarySecurityScreen(false /*turningOff*/);
+            return true;
+        }
         if (mCurrentSecuritySelection != SecurityMode.None) {
             mCallback.dismiss(false);
             return true;