Add await mechanism to setClipboard in android_semantics_integration test (flutter#185428)

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fixes flutter#184755

The failure suggest there may be race condition when setClipboard async
update the OS while TextField receive canPaste signal. Adding an await
mechanism to see if that eliminate the race condition.


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Author: chunhtai

dev/integration_tests/android_semantics_testing/android/app/src/main/java/com/yourcompany/platforminteraction/MainActivity.java

@@ -72,9 +72,40 @@ public void onMethodCall(MethodCall methodCall, MethodChannel.Result result) {
             @SuppressWarnings("unchecked")
             String message = (String) data.get("message");
             ClipboardManager clipboard = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
+
+            if (clipboard.hasPrimaryClip()) {
+                ClipData currentClip = clipboard.getPrimaryClip();
+                if (currentClip != null && currentClip.getItemCount() > 0) {
+                    CharSequence text = currentClip.getItemAt(0).getText();
+                    if (text != null && text.toString().equals(message)) {
+                        // The clipboard already has the expected value, no need to set it.
+                        result.success(null);
+                        return;
+                    }
+                }
+            }
+
+            // To avoid race conditions during integration tests, wait until the system has
+            // completed the clipboard update before returning success to the test runner.
+            ClipboardManager.OnPrimaryClipChangedListener listener = new ClipboardManager.OnPrimaryClipChangedListener() {
+                @Override
+                public void onPrimaryClipChanged() {
+                    ClipData currentClip = clipboard.getPrimaryClip();
+                    if (currentClip != null && currentClip.getItemCount() > 0) {
+                        CharSequence text = currentClip.getItemAt(0).getText();
+                        // Verify if the clipboard has the correct value before returning success to the test runner.
+                        if (text != null && text.toString().equals(message)) {
+                            clipboard.removePrimaryClipChangedListener(this);
+                            result.success(null);
+                            return;
+                        }
+                    }
+                }
+            };
+
+            clipboard.addPrimaryClipChangedListener(listener);
             ClipData clip = ClipData.newPlainText("message", message);
             clipboard.setPrimaryClip(clip);
-            result.success(null);
             return;
         }
         result.notImplemented();