Handle input method switch properly for inline suggestions

Expired the old response while received input method subtype changed.
When user next tap on an autofill field, trigger a new fill request for
the new input method.

Bug: 150483555
Test: manual switch imput method
Test: atest CtsAutoFillServiceTestCases
Change-Id: I97be067db3a79d2481c05aeb59875ec24514199d

services/autofill/java/com/android/server/autofill/AutofillManagerService.java

@@ -249,6 +249,9 @@ public final class AutofillManagerService
         resolver.registerContentObserver(Settings.Global.getUriFor(
                 Settings.Global.AUTOFILL_MAX_VISIBLE_DATASETS), false, observer,
                 UserHandle.USER_ALL);
+        resolver.registerContentObserver(Settings.Secure.getUriFor(
+                Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE), false, observer,
+                UserHandle.USER_ALL);
     }
 
     @Override // from AbstractMasterSystemService
@@ -263,6 +266,9 @@ public final class AutofillManagerService
             case Settings.Global.AUTOFILL_MAX_VISIBLE_DATASETS:
                 setMaxVisibleDatasetsFromSettings();
                 break;
+            case Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE:
+                handleInputMethodSwitch(userId);
+                break;
             default:
                 Slog.w(TAG, "Unexpected property (" + property + "); updating cache instead");
                 // fall through
@@ -273,6 +279,23 @@ public final class AutofillManagerService
         }
     }
 
+    private void handleInputMethodSwitch(@UserIdInt int userId) {
+        // TODO(b/156903336): Used the SettingsObserver with a background thread maybe slow to
+        // respond to the IME switch in certain situations.
+        // See: services/core/java/com/android/server/FgThread.java
+        // In particular, the shared background thread could be doing relatively long-running
+        // operations like saving state to disk (in addition to simply being a background priority),
+        // which can cause operations scheduled on it to be delayed for a user-noticeable amount
+        // of time.
+
+        synchronized (mLock) {
+            final AutofillManagerServiceImpl service = peekServiceForUserLocked(userId);
+            if (service != null) {
+                service.onSwitchInputMethod();
+            }
+        }
+    }
+
     private void onDeviceConfigChange(@NonNull Set<String> keys) {
         for (String key : keys) {
             switch (key) {

services/autofill/java/com/android/server/autofill/AutofillManagerServiceImpl.java

@@ -1564,6 +1564,16 @@ final class AutofillManagerServiceImpl
         }
     }
 
+    void onSwitchInputMethod() {
+        synchronized (mLock) {
+            final int sessionCount = mSessions.size();
+            for (int i = 0; i < sessionCount; i++) {
+                final Session session = mSessions.valueAt(i);
+                session.onSwitchInputMethodLocked();
+            }
+        }
+    }
+
     @Override
     public String toString() {
         return "AutofillManagerServiceImpl: [userId=" + mUserId

services/autofill/java/com/android/server/autofill/Session.java

@@ -311,6 +311,43 @@ final class Session implements RemoteFillService.FillServiceCallbacks, ViewState
      */
     private final AssistDataReceiverImpl mAssistReceiver = new AssistDataReceiverImpl();
 
+    void onSwitchInputMethodLocked() {
+        if (mExpiredResponse) {
+            return;
+        }
+
+        if (shouldExpireResponseOnInputMethodSwitch()) {
+            // Set the old response expired, so the next action (ACTION_VIEW_ENTERED) can trigger
+            // a new fill request.
+            mExpiredResponse = true;
+        }
+    }
+
+    private boolean shouldExpireResponseOnInputMethodSwitch() {
+        // One of below cases will need a new fill request to update the inline spec for the new
+        // input method.
+        // 1. The autofill provider supports inline suggestion and the render service is available.
+        // 2. Had triggered the augmented autofill and the render service is available. Whether the
+        // augmented autofill triggered by:
+        //    a. Augmented autofill only
+        //    b. The autofill provider respond null
+        if (mService.getRemoteInlineSuggestionRenderServiceLocked() == null) {
+            return false;
+        }
+
+        if (isInlineSuggestionsEnabledByAutofillProviderLocked()) {
+            return true;
+        }
+
+        final ViewState state = mViewStates.get(mCurrentViewId);
+        if (state != null
+                && (state.getState() & ViewState.STATE_TRIGGERED_AUGMENTED_AUTOFILL) != 0) {
+            return true;
+        }
+
+        return false;
+    }
+
     /**
      * TODO(b/151867668): improve how asynchronous data dependencies are handled, without using
      * CountDownLatch.