Allow muted third-party autoplay with -ormuted experiment option.

third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/html/AutoplayExperimentHelper.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/layout/LayoutBox.h"
@@ skipping 112 matching lines @@
 }
 
 void AutoplayExperimentHelper::loadMethodCalled()
 {
     if (isLockedPendingUserGesture() && UserGestureIndicator::utilizeUserGesture()) {
         recordAutoplayMetric(AutoplayEnabledThroughLoad);
         unlockUserGesture(GesturelessPlaybackEnabledByLoad);
     }
 }
 
+void AutoplayExperimentHelper::mutedChanged()
+{
+    // Mute changes are always allowed if this is unlocked.
+    if (!client().isLockedPendingUserGesture())
+        return;
+
+    // Changes with a user gesture are okay.
+    if (UserGestureIndicator::utilizeUserGesture())
+        return;
+
+    // If the mute state has changed to 'muted', then it's okay.
+    if (client().muted())
+        return;
+
+    // If nothing is playing, then changes are okay too.
+    if (client().paused())
+        return;
+
+    // Trying to unmute without a user gesture.
+
+    // If we don't care about muted state, then it's okay.
+    if (!enabled(IfMuted) && !(client().isCrossOrigin() && enabled(OrMuted)))
+        return;
+
+    // Unmuting isn't allowed, so pause.
+    client().pauseInternal();
+}
+
 void AutoplayExperimentHelper::registerForPositionUpdatesIfNeeded()
 {
     // If we don't require that the player is in the viewport, then we don't
     // need the listener.
     if (!requiresViewportVisibility()) {
         if (!enabled(IfPageVisible))
             return;
     }
 
     m_client->setRequestPositionUpdates(true);
@@ skipping 177 matching lines @@
     if (mode !=  IgnorePendingPlayback && !m_playPending && !client().shouldAutoplay())
         return false;
 
     // Note that the viewport test always returns false on desktop, which is
     // why video-autoplay-experiment.html doesn't check -ifmobile .
     if (enabled(IfMobile)
         && !client().isLegacyViewportType())
         return false;
 
     // If we require same-origin, then check the origin.
-    if (enabled(IfSameOrigin) && client().isCrossOrigin())
-        return false;
+    if (enabled(IfSameOrigin) && client().isCrossOrigin()) {
+        // We're cross-origin, so block unless it's muted content and OrMuted
+        // is enabled.  For good measure, we also block all audio elements.
+        if (client().isHTMLAudioElement() || !client().muted()
+            || !enabled(OrMuted)) {
+            return false;
+        }
+    }
 
     // If we require muted media and this is muted, then it is eligible.
     if (enabled(IfMuted))
         return client().muted();
 
     // Element is eligible for gesture override, maybe muted.
     return true;
 }
 
 void AutoplayExperimentHelper::muteIfNeeded()
@@ skipping 58 matching lines @@
     if (mode.contains("-ifviewport"))
         value |= IfViewport;
     if (mode.contains("-ifpartialviewport"))
         value |= IfPartialViewport;
     if (mode.contains("-ifmuted"))
         value |= IfMuted;
     if (mode.contains("-ifmobile"))
         value |= IfMobile;
     if (mode.contains("-ifsameorigin"))
         value |= IfSameOrigin;
+    if (mode.contains("-ormuted"))
+        value |= OrMuted;
     if (mode.contains("-playmuted"))
         value |= PlayMuted;
 
     return value;
 }
 
 void AutoplayExperimentHelper::autoplayMediaEncountered()
 {
     if (!m_autoplayMediaEncountered) {
         m_autoplayMediaEncountered = true;
@@ skipping 93 matching lines @@
 {
     return client().isHTMLVideoElement() && (enabled(IfViewport) || enabled(IfPartialViewport));
 }
 
 bool AutoplayExperimentHelper::isExperimentEnabled()
 {
     return m_mode != Mode::ExperimentOff;
 }
 
 } // namespace blink