Introduce StartInputReason.SCHEDULED_CHECK_FOCUS

With this CL,

  adb shell dumpsys input_method,

tells us about whether startInputInner() is triggered by

  InputMethodManager.DelegateImpl#onScheduledCheckFocus()

or

  InputMethodManager#checkFocus().

Other than that there must be no observable behavior change.

Bug: 234882948
Test: presubmit
Change-Id: I54ebf1a4e1f749ce265756908ef52fc63f1218e5

core/java/android/view/inputmethod/InputMethodManager.java

@@ -789,7 +789,7 @@ public final class InputMethodManager {
                 }
             }
 
-            if (checkFocusInternal(forceNewFocus, false, viewRootImpl)) {
+            if (checkFocusInternal(forceNewFocus, viewRootImpl)) {
                 // We need to restart input on the current focus view.  This
                 // should be done in conjunction with telling the system service
                 // about the window gaining focus, to help make the transition
@@ -826,7 +826,12 @@ public final class InputMethodManager {
 
         @Override
         public void onScheduledCheckFocus(@NonNull ViewRootImpl viewRootImpl) {
-            checkFocusInternal(false, true, viewRootImpl);
+            if (!checkFocusInternal(false, viewRootImpl)) {
+                return;
+            }
+            startInputOnWindowFocusGainInternal(StartInputReason.SCHEDULED_CHECK_FOCUS,
+                    null /* focusedView */, 0 /* startInputFlags */, 0 /* softInputMode */,
+                    0 /* windowFlags */);
         }
 
         @Override
@@ -1118,7 +1123,7 @@ public final class InputMethodManager {
                         if (mCurRootView == null) {
                             return;
                         }
-                        if (!checkFocusInternal(mRestartOnNextWindowFocus, false, mCurRootView)) {
+                        if (!checkFocusInternal(mRestartOnNextWindowFocus, mCurRootView)) {
                             return;
                         }
                         final int reason = active ? StartInputReason.ACTIVATED_BY_IMMS
@@ -2338,8 +2343,7 @@ public final class InputMethodManager {
     }
 
     /**
-     * Called from {@link #checkFocusInternal(boolean, boolean, ViewRootImpl)},
-     * {@link #restartInput(View)}, {@link #MSG_BIND} or {@link #MSG_UNBIND}.
+     * Starts an input connection from the served view that gains the window focus.
      * Note that this method should *NOT* be called inside of {@code mH} lock to prevent start input
      * background thread may blocked by other methods which already inside {@code mH} lock.
      */
@@ -2660,14 +2664,18 @@ public final class InputMethodManager {
             }
             viewRootImpl = mCurRootView;
         }
-        checkFocusInternal(false /* forceNewFocus */, true /* startInput */, viewRootImpl);
+        if (!checkFocusInternal(false /* forceNewFocus */, viewRootImpl)) {
+            return;
+        }
+        startInputOnWindowFocusGainInternal(StartInputReason.CHECK_FOCUS,
+                null /* focusedView */,
+                0 /* startInputFlags */, 0 /* softInputMode */, 0 /* windowFlags */);
     }
 
     /**
      * Check the next served view if needs to start input.
      */
-    private boolean checkFocusInternal(boolean forceNewFocus, boolean startInput,
-            ViewRootImpl viewRootImpl) {
+    private boolean checkFocusInternal(boolean forceNewFocus, ViewRootImpl viewRootImpl) {
         synchronized (mH) {
             if (mCurRootView != viewRootImpl) {
                 return false;
@@ -2694,12 +2702,6 @@ public final class InputMethodManager {
                 mServedInputConnection.finishComposingTextFromImm();
             }
         }
-
-        if (startInput) {
-            startInputOnWindowFocusGainInternal(StartInputReason.CHECK_FOCUS,
-                    null /* focusedView */,
-                    0 /* startInputFlags */, 0 /* softInputMode */, 0 /* windowFlags */);
-        }
         return true;
     }
 

core/java/com/android/internal/inputmethod/InputMethodDebug.java

@@ -49,6 +49,8 @@ public final class InputMethodDebug {
                 return "WINDOW_FOCUS_GAIN";
             case StartInputReason.WINDOW_FOCUS_GAIN_REPORT_ONLY:
                 return "WINDOW_FOCUS_GAIN_REPORT_ONLY";
+            case StartInputReason.SCHEDULED_CHECK_FOCUS:
+                return "SCHEDULED_CHECK_FOCUS";
             case StartInputReason.APP_CALLED_RESTART_INPUT_API:
                 return "APP_CALLED_RESTART_INPUT_API";
             case StartInputReason.CHECK_FOCUS:

core/java/com/android/internal/inputmethod/StartInputReason.java

@@ -31,6 +31,7 @@ import java.lang.annotation.Retention;
         StartInputReason.UNSPECIFIED,
         StartInputReason.WINDOW_FOCUS_GAIN,
         StartInputReason.WINDOW_FOCUS_GAIN_REPORT_ONLY,
+        StartInputReason.SCHEDULED_CHECK_FOCUS,
         StartInputReason.APP_CALLED_RESTART_INPUT_API,
         StartInputReason.CHECK_FOCUS,
         StartInputReason.BOUND_TO_IMMS,
@@ -57,6 +58,11 @@ public @interface StartInputReason {
      * this window focus change event to sync IME input target for system.
      */
     int WINDOW_FOCUS_GAIN_REPORT_ONLY = 2;
+    /**
+     * Similar to {@link #CHECK_FOCUS}, but the one scheduled with
+     * {@link android.view.ViewRootImpl#dispatchCheckFocus()}.
+     */
+    int SCHEDULED_CHECK_FOCUS = 3;
     /**
      * {@link android.view.inputmethod.InputMethodManager#restartInput(android.view.View)} is
      * either explicitly called by the application or indirectly called by some Framework class