[Edge] Cancel the timer from running when we are done with it

Each use of a timer creates a User Object in Windows, and once we
have stopped waiting for our desired event we don't need the cancellation
tracking anymore.

If there are lots of calls to processOSMessagesUntil, such as repeated
browser.setText within the MAXIMUM_OPERATION_TIME (5 second) window,
we can end up with a huge growth in the number of User Objects, leading
to potential `SWTError: No more handles` errors elsewhere in the client
code.

Fixes #2806

Author: jonahgraham

bundles/org.eclipse.swt/Eclipse SWT Browser/win32/org/eclipse/swt/browser/Edge.java

@@ -551,14 +551,16 @@ private static void processOSMessagesUntil(Supplier<Boolean> condition, Consumer
 	MSG msg = new MSG();
 	AtomicBoolean timeoutOccurred = new AtomicBoolean();
 	// The timer call also wakes up the display to avoid being stuck in display.sleep()
-	display.timerExec((int) MAXIMUM_OPERATION_TIME.toMillis(), () -> timeoutOccurred.set(true));
+	Runnable runnable = () -> timeoutOccurred.set(true);
+	display.timerExec((int) MAXIMUM_OPERATION_TIME.toMillis(), runnable);
 	while (!display.isDisposed() && !condition.get() && !timeoutOccurred.get()) {
 		if (OS.PeekMessage(msg, 0, 0, 0, OS.PM_NOREMOVE | OS.PM_QS_POSTMESSAGE)) {
 			display.readAndDispatch();
 		} else {
 			display.sleep();
 		}
 	}
+	display.timerExec(-1, runnable);
 	if (!condition.get()) {
 		timeoutHandler.accept(createTimeOutException());
 	}

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java

@@ -77,6 +77,7 @@
 import org.eclipse.swt.events.FocusListener;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Shell;
@@ -2754,6 +2755,18 @@ public void test_TabTraversalOutOfBrowser() {
 	assertTrue(text.isFocusControl());
 }
 
+// Regression test for https://github.com/eclipse-platform/eclipse.platform.swt/issues/2806
+@Test
+public void test_TimerRegression_Issue2806() {
+	for (int i = 0; i < 10000; i++) {
+		browser.setText("Iteration " + i);
+		new BrowserFunction(browser, "name");
+	}
+	new Composite(shell, SWT.NONE);
+	processUiEvents();
+
+}
+
 /* custom */
 /**
  * Wait for passTest to return true. Timeout otherwise.