[Picture-in-Picture] Fix browser_tests flakyness.

This makes sure video loaded in a iframe is loaded before attempting
requesting Picture-in-Picture in browser_tests.

Bug: 853643
Change-Id: I2ad236ac24d42a89194e3dbb9ace4b9f56961d92
Reviewed-on: https://chromium-review.googlesource.com/1103570
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: apacible <apacible@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569581}

chrome/browser/picture_in_picture/picture_in_picture_window_controller_browsertest.cc

@@ -598,6 +598,12 @@ IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
           ? render_frame_hosts[1]
           : render_frame_hosts[0];
 
+  // Wait for video metadata to load.
+  base::string16 expected_title = base::ASCIIToUTF16("loadedmetadata");
+  EXPECT_EQ(expected_title,
+            content::TitleWatcher(active_web_contents, expected_title)
+                .WaitAndGetTitle());
+
   std::string result;
   ASSERT_TRUE(content::ExecuteScriptAndExtractString(
       iframe, "enterPictureInPicture();", &result));
@@ -611,17 +617,8 @@ IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
   EXPECT_FALSE(window_controller()->GetWindowForTesting()->IsVisible());
 }
 
-// Same as above for a cross-origin iframe.
-// Flaky on windows and Linux: crbug/854349
-#if defined(OS_WIN) || defined(OS_LINUX)
-#define MAYBE_CrossOriginFrameEnterLeaveCloseWindow \
-  DISABLED_CrossOriginFrameEnterLeaveCloseWindow
-#else
-#define MAYBE_CrossOriginFrameEnterLeaveCloseWindow \
-  CrossOriginFrameEnterLeaveCloseWindow
-#endif
 IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
-                       MAYBE_CrossOriginFrameEnterLeaveCloseWindow) {
+                       CrossOriginFrameEnterLeaveCloseWindow) {
   GURL embed_url = embedded_test_server()->GetURL(
       "a.com", "/media/picture-in-picture/iframe-content.html");
   GURL main_url = embedded_test_server()->GetURL(
@@ -645,6 +642,12 @@ IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
           ? render_frame_hosts[1]
           : render_frame_hosts[0];
 
+  // Wait for video metadata to load.
+  base::string16 expected_title = base::ASCIIToUTF16("loadedmetadata");
+  EXPECT_EQ(expected_title,
+            content::TitleWatcher(active_web_contents, expected_title)
+                .WaitAndGetTitle());
+
   std::string result;
   ASSERT_TRUE(content::ExecuteScriptAndExtractString(
       iframe, "enterPictureInPicture();", &result));

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

@@ -9,6 +9,10 @@
 <script>
   const video = document.querySelector('video');
 
+  video.addEventListener('loadedmetadata', function() {
+    window.parent.postMessage({ loadedmetadata: true }, '*');
+  });
+
   function enterPictureInPicture() {
     video.requestPictureInPicture().then(() => {
       domAutomationController.send('done');

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

@@ -18,5 +18,11 @@
   function removeFrame() {
     document.body.removeChild(document.querySelector('iframe'));
   }
+
+  window.addEventListener('message', function(event) {
+    if (event.data.loadedmetadata) {
+      document.title = 'loadedmetadata';
+    }
+  });
 </script>
 </html>