Picture-in-Picture: refactor browser tests to not use a resize counter.

Bug: None
Change-Id: I962397a6c916b176970a451093bcef82bea83258
Reviewed-on: https://chromium-review.googlesource.com/1125403Reviewed-by: apacible <apacible@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572447}

chrome/test/data/media/picture-in-picture/iframe-content.html

@@ -15,7 +15,7 @@
 
   function enterPictureInPicture() {
     video.requestPictureInPicture().then(() => {
-      domAutomationController.send('done');
+      domAutomationController.send(true);
     });
   }
 

chrome/test/data/media/picture-in-picture/player_metadata_poster.html

@@ -3,7 +3,7 @@
 <script>
   function enterPictureInPicture() {
     document.querySelector('video').requestPictureInPicture().then(() => {
-      document.title = 'entered_pip';
+      window.domAutomationController.send(true);
     });
   }
 </script>

chrome/test/data/media/picture-in-picture/window-size.html

@@ -8,8 +8,6 @@
 </body>
 <script>
   const video = document.querySelector('video');
-  let pipWindow = null;
-  let sizeCountUpdates = 0;
 
   // This video is created here in order to be used in
   // `secondPictureInPicture()`. Unfortunately, the `requestPictureInPicture()`
@@ -19,13 +17,6 @@
   secondVideo.src = '../bigbuck.webm';
   secondVideo.load();
 
-  function updateTitle() {
-    // TODO(mlamouri): ideally, we should send the actual size but it will be
-    // flaky and require some minutia so starting with the basics.
-    sizeCountUpdates++;
-    document.title = sizeCountUpdates;
-  }
-
   function requestPictureInPictureAndDisable() {
     enterPictureInPictureInternal();
     video.disablePictureInPicture = true;
@@ -50,16 +41,18 @@
   function enterPictureInPictureInternal() {
     video.requestPictureInPicture()
     .then(win => {
-      pipWindow = win;
-      updateTitle();
-      pipWindow.addEventListener('resize', updateTitle);
+      win.addEventListener('resize', () => {
+        document.title = 'resized';
+      }, { once: true });
 
       video.addEventListener('leavepictureinpicture', () => {
         document.title = 'left';
       }, { once: true });
+
+      window.domAutomationController.send(true);
     })
     .catch(e => {
-      document.title = 'rejected';
+      window.domAutomationController.send(false);
     });
   }