[Paint Preview] Add first paint check to player test

Check for first paint before proceeding.

Bug: 1136907, 1136956
Change-Id: Ibcd835a07ed9ba120873b07081824f03674fc41e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2469262
Commit-Queue: Calder Kitagawa <ckitagawa@chromium.org>
Auto-Submit: Calder Kitagawa <ckitagawa@chromium.org>
Reviewed-by: Mehran Mahmoudi <mahmoudi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817059}

components/paint_preview/player/android/javatests/src/org/chromium/components/paintpreview/player/PaintPreviewPlayerTest.java

@@ -365,6 +365,7 @@ public class PaintPreviewPlayerTest extends DummyUiActivityTestCase {
         mLinkClickHandler = new TestLinkClickHandler();
         mRefreshedCallback = new CallbackHelper();
         CallbackHelper viewReady = new CallbackHelper();
+        CallbackHelper firstPaint = new CallbackHelper();
         mInitializationFailed = false;
 
         PostTask.postTask(UiThreadTaskTraits.DEFAULT, () -> {
@@ -389,7 +390,9 @@ public class PaintPreviewPlayerTest extends DummyUiActivityTestCase {
                         }
 
                         @Override
-                        public void onFirstPaint() {}
+                        public void onFirstPaint() {
+                            firstPaint.notifyCalled();
+                        }
 
                         @Override
                         public void onUserInteraction() {}
@@ -441,6 +444,12 @@ public class PaintPreviewPlayerTest extends DummyUiActivityTestCase {
         if (mInitializationFailed) {
             Assert.fail("Compositor may have crashed.");
         }
+
+        try {
+            firstPaint.waitForFirst();
+        } catch (Exception e) {
+            Assert.fail("First paint not issued.");
+        }
     }
 
     /*