Send empty response to IME when autofill session is destroyed

* Note that usually the session is destroyed when the focus is
  already on a new input field in a different activity, so this
  action will be no-op most of the cases
* But in case of augmented autofill service dynamically requesting
  a new autofill flow, this works well on clearing the existing
  suggestions on the current input field

Test: manual
Test: atest android.autofillservice.cts.inline
Bug: 157515522
Bug: 158038231

Change-Id: I6cedb33737d822c3c3eb4ee127984c24c4307f7a

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

@@ -77,8 +77,8 @@ final class AutofillInlineSessionController {
         if (mSession != null) {
             // Destroy the existing session.
             mSession.destroySessionLocked();
-            mInlineFillUi = null;
         }
+        mInlineFillUi = null;
         // TODO(b/151123764): consider reusing the same AutofillInlineSession object for the
         // same field.
         mSession = new AutofillInlineSuggestionsRequestSession(mInputMethodManagerInternal, mUserId,
@@ -86,6 +86,22 @@ final class AutofillInlineSessionController {
         mSession.onCreateInlineSuggestionsRequestLocked();
     }
 
+    /**
+     * Destroys the current session. May send an empty response to IME to clear the suggestions if
+     * the focus didn't change to a different field.
+     *
+     * @param autofillId the currently focused view from the autofill session
+     */
+    @GuardedBy("mLock")
+    void destroyLocked(@NonNull AutofillId autofillId) {
+        if (mSession != null) {
+            mSession.onInlineSuggestionsResponseLocked(InlineFillUi.emptyUi(autofillId));
+            mSession.destroySessionLocked();
+            mSession = null;
+        }
+        mInlineFillUi = null;
+    }
+
     /**
      * Returns the {@link InlineSuggestionsRequest} provided by IME for the last request.
      *

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

@@ -3702,6 +3702,9 @@ final class Session implements RemoteFillService.FillServiceCallbacks, ViewState
         unlinkClientVultureLocked();
         mUi.destroyAll(mPendingSaveUi, this, true);
         mUi.clearCallback(this);
+        if (mCurrentViewId != null) {
+            mInlineSessionController.destroyLocked(mCurrentViewId);
+        }
         mDestroyed = true;
 
         // Log metrics