Add a hold-by-name gesture to ui-trace

A row held to select it was the one gesture that could only be written as a
pair of coordinates: `tap`'s press is 60ms so nothing sees a long press, and
`holddrag` takes numbers and always drags afterwards. `hold 'helper 3'`
resolves the label the way `tap` does -- the resolution is now `locate`,
shared by both -- and holds the press past the platform's 500ms threshold.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

share/ui-trace/UiTrace.java

@@ -33,6 +33,8 @@ public final class UiTrace {
     private static final int MAX_DEPTH = 60;
     /** How long `tap LABEL` keeps looking before it decides the label is not there. */
     private static final long FIND_TIMEOUT_MS = 3000;
+    /** Comfortably past the platform's 500ms long-press threshold, for `hold`. */
+    private static final long HOLD_MS = 800;
 
     private final UiAutomation automation;
     private final PrintWriter out;
@@ -218,6 +220,7 @@ public final class UiTrace {
                     tapLabel(join(step));
                 }
             }
+            case "hold" -> holdLabel(join(step));
             case "swipe" -> swipe(Integer.parseInt(step[1]), Integer.parseInt(step[2]),
                     Integer.parseInt(step[3]), Integer.parseInt(step[4]),
                     step.length > 5 ? Long.parseLong(step[5]) : 300);
@@ -253,21 +256,48 @@ public final class UiTrace {
         return label;
     }
 
+    /** Presses whatever is currently labelled `label`, wherever it is. */
+    private void tapLabel(String label) {
+        Rect box = locate(label, "tap");
+        tap(box.centerX(), box.centerY());
+    }
+
     /**
-     * Presses whatever is currently labelled `label`, wherever it is.
+     * Presses whatever is labelled `label` and holds it past the platform's long-press
+     * threshold, then lets go without moving.
      *
-     * This is the action to reach for, and `tap X Y` is the exception. A coordinate is a position
-     * measured once by hand: anything that moves the thing being pressed -- a control added to the
-     * row, a font size, a density, a different device -- makes the tap land on whatever now sits
-     * there, and the script then reports a number that was never measured, which reads exactly
-     * like a result. A name is what the control already carries for assistive technology, so it
-     * survives all of that and fails loudly when it genuinely is not there.
+     * `tap` cannot reach this: its press is 60ms, so nothing that distinguishes a press from a
+     * long press ever sees one. `holddrag` can hold, but it takes coordinates and always drags
+     * afterwards -- so the one gesture a list's "hold a row to select it" needs was the one
+     * gesture that could only be written as a pair of numbers, which is exactly what a script
+     * driving a UI must not contain.
+     */
+    private void holdLabel(String label) {
+        Rect box = locate(label, "hold");
+        int x = box.centerX(), y = box.centerY();
+        long down = SystemClock.uptimeMillis();
+        send(MotionEvent.ACTION_DOWN, down, x, y);
+        SystemClock.sleep(HOLD_MS);
+        send(MotionEvent.ACTION_UP, down, x, y);
+    }
+
+    /**
+     * Where whatever is currently labelled `label` is on screen, for the `verb` about to press
+     * it.
+     *
+     * Pressing by name is the action to reach for, and a coordinate is the exception. A
+     * coordinate is a position measured once by hand: anything that moves the thing being
+     * pressed -- a control added to the row, a font size, a density, a different device -- makes
+     * the press land on whatever now sits there, and the script then reports a number that was
+     * never measured, which reads exactly like a result. A name is what the control already
+     * carries for assistive technology, so it survives all of that and fails loudly when it
+     * genuinely is not there.
      *
      * The box is read from the tree at the moment of the gesture rather than from an earlier
      * frame, because the screen the gesture lands on is the only one that decides where the mark
      * is.
      */
-    private void tapLabel(String label) {
+    private Rect locate(String label, String verb) {
         // Looked for repeatedly for a moment rather than once. Two things make a single look
         // wrong: the accessibility connection has no window at all for the first frames after it
         // is made, so an action at the very start of a trace found nothing to search; and a
@@ -299,11 +329,12 @@ public final class UiTrace {
             throw new IllegalStateException("\"" + label + "\" has no size on screen");
         }
         synchronized (out) {
-            out.println("# tap \"" + label + "\" at " + box.centerX() + "," + box.centerY()
-                    + " in " + box.left + "," + box.top + "," + box.right + "," + box.bottom);
+            out.println("# " + verb + " \"" + label + "\" at " + box.centerX() + ","
+                    + box.centerY() + " in " + box.left + "," + box.top + "," + box.right + ","
+                    + box.bottom);
             out.flush();
         }
-        tap(box.centerX(), box.centerY());
+        return box;
     }
 
     /** Every visible node whose text or description is exactly `label`, in tree order. */