Add partial viewport visibility check to autoplay experiment.

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 130 matching lines @@
         // Try to play.  If we can't, then install a listener.
         if (!maybeStartPlaying())
             registerForPositionUpdatesIfNeeded();
     }
 }
 
 void AutoplayExperimentHelper::registerForPositionUpdatesIfNeeded()
 {
     // If we don't require that the player is in the viewport, then we don't
     // need the listener.
-    if (!enabled(IfViewport)) {
+    if (!requiresViewportVisibility()) {
         if (!enabled(IfPageVisible))
             return;
     }
 
     m_client->setRequestPositionUpdates(true);
 
     // Set this unconditionally, in case we have no layout object yet.
     m_registeredWithLayoutObject = true;
 }
 
@@ skipping 70 matching lines @@
     // treat it as the end of scroll.  Autoplay if we should.
     maybeStartPlaying();
 }
 
 bool AutoplayExperimentHelper::meetsVisibilityRequirements() const
 {
     if (enabled(IfPageVisible)
         && client().pageVisibilityState() != PageVisibilityStateVisible)
         return false;
 
-    if (!enabled(IfViewport))
+    if (!requiresViewportVisibility())
         return true;
 
     if (m_lastVisibleRect.isEmpty())
         return false;
 
     IntRect currentLocation = client().absoluteBoundingBoxRect();
     if (currentLocation.isEmpty())
         return false;
 
+    // In partial-viewport mode, we require only 1x1 area.
+    if (enabled(IfPartialViewport)) {
+        return m_lastVisibleRect.intersects(currentLocation);
+    }
+
+    // Element must be completely visible, or as much as fits.
     // If element completely fills the screen, then truncate it to exactly
     // match the screen.  Any element that is wider just has to cover.
     if (currentLocation.x() <= m_lastVisibleRect.x()
         && currentLocation.x() + currentLocation.width() >= m_lastVisibleRect.x() + m_lastVisibleRect.width()) {
         currentLocation.setX(m_lastVisibleRect.x());
         currentLocation.setWidth(m_lastVisibleRect.width());
     }
 
     if (currentLocation.y() <= m_lastVisibleRect.y()
         && currentLocation.y() + currentLocation.height() >= m_lastVisibleRect.y() + m_lastVisibleRect.height()) {
@@ skipping 113 matching lines @@
 {
     Mode value = ExperimentOff;
     if (mode.contains("-forvideo"))
         value |= ForVideo;
     if (mode.contains("-foraudio"))
         value |= ForAudio;
     if (mode.contains("-ifpagevisible"))
         value |= IfPageVisible;
     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("-playmuted"))
         value |= PlayMuted;
 
     return value;
 }
 
@@ skipping 75 matching lines @@
 {
     if (m_recordedElement)
         return;
 
     m_recordedElement = true;
     recordAutoplayMetric(client().isHTMLVideoElement()
         ? AnyVideoElement
         : AnyAudioElement);
 }
 
+bool AutoplayExperimentHelper::requiresViewportVisibility() const
+{
+    return enabled(IfViewport) || enabled(IfPartialViewport);
+}
+
 } // namespace blink