Allow the ChromeOS Video Player app to use <video> autoPictureInPicture

Following low-latency canvas for PDF annotations feature approach, this
CL makes sure Auto Picture-in-Picture is enabled for the built-in Chrome
OS video player app.

https://chromium-review.googlesource.com/c/chromium/src/+/1506916
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/eFZ3h_A3VTY

Bug: 938226
Change-Id: I0a1bd32130612a5ab1d2034751df293c76669ed1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1508400
Auto-Submit: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Reviewed-by: dstockwell <dstockwell@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: dstockwell <dstockwell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640206}
diff --git a/chrome/browser/chromeos/file_manager/video_player_browsertest.cc b/chrome/browser/chromeos/file_manager/video_player_browsertest.cc
index a671371d..d30ca64 100644
--- a/chrome/browser/chromeos/file_manager/video_player_browsertest.cc
+++ b/chrome/browser/chromeos/file_manager/video_player_browsertest.cc
@@ -6,7 +6,6 @@
 
 #include "base/test/scoped_feature_list.h"
 #include "chromeos/constants/chromeos_switches.h"
-#include "content/public/common/content_switches.h"
 #include "media/base/media_switches.h"
 
 namespace file_manager {
@@ -20,11 +19,6 @@
   void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitch(
         chromeos::switches::kEnableVideoPlayerChromecastSupport);
-    // TODO(crbug.com/938226): Remove when Auto Picture-in-Picture is not
-    // experimental anymore.
-    command_line->AppendSwitch(
-        switches::kEnableExperimentalWebPlatformFeatures);
-
     FileManagerBrowserTestBase::SetUpCommandLine(command_line);
   }
 
diff --git a/third_party/blink/renderer/core/loader/document_loader.cc b/third_party/blink/renderer/core/loader/document_loader.cc
index c14b0b4..f87c474 100644
--- a/third_party/blink/renderer/core/loader/document_loader.cc
+++ b/third_party/blink/renderer/core/loader/document_loader.cc
@@ -1522,6 +1522,14 @@
       OriginTrialContext::FromOrCreate(document)->AddFeature(
           origin_trials::kLowLatencyCanvasTrialName);
     }
+    // Enable Auto Picture-in-Picture feature for the built-in Chrome OS Video
+    // Player app.
+    if (origin.scheme() == "chrome-extension" &&
+        origin.DomainIs("jcgeabjmjgoblfofpppfkcoakmfobdko") &&
+        origin.port() == 0) {
+      OriginTrialContext::FromOrCreate(document)->AddFeature(
+          origin_trials::kAutoPictureInPictureTrialName);
+    }
 #endif
 
     OriginTrialContext::AddTokensFromHeader(