Add partial viewport visibility check to autoplay experiment.

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

 // Copyright 2015 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.
 
 #ifndef AutoplayExperimentHelper_h
 #define AutoplayExperimentHelper_h
 
 #include "core/page/Page.h"
 #include "platform/Timer.h"
 #include "platform/geometry/IntRect.h"
@@ skipping 146 matching lines @@
 
     // Remove the user gesture requirement, and record why.  If there is no
     // gesture requirement, then this does nothing.
     void removeUserGestureRequirement(AutoplayMetrics);
 
     // Set the position to the current view's position, and
     void triggerAutoplayViewportCheckForTesting();
 
     enum Mode {
         // Do not enable the autoplay experiment.
-        ExperimentOff = 0,
+        ExperimentOff     = 0,
         // Enable gestureless autoplay for video elements.
-        ForVideo      = 1 << 0,
+        ForVideo          = 1 << 0,
         // Enable gestureless autoplay for audio elements.
-        ForAudio      = 1 << 1,
+        ForAudio          = 1 << 1,
         // Restrict gestureless autoplay to media that is in a visible page.
-        IfPageVisible = 1 << 2,
-        // Restrict gestureless autoplay to media that is visible in
+        IfPageVisible     = 1 << 2,
+        // Restrict gestureless autoplay to media that is entirely visible in
         // the viewport.
-        IfViewport    = 1 << 3,
+        IfViewport        = 1 << 3,
+        // Restrict gestureless autoplay to media that is partially visible in
+        // the viewport.
+        IfPartialViewport = 1 << 4,
         // Restrict gestureless autoplay to audio-less or muted media.
-        IfMuted       = 1 << 4,
+        IfMuted           = 1 << 5,
         // Restrict gestureless autoplay to sites which contain the
         // viewport tag.
-        IfMobile      = 1 << 5,
+        IfMobile          = 1 << 6,
         // If gestureless autoplay is allowed, then mute the media before
         // starting to play.
-        PlayMuted     = 1 << 6,
+        PlayMuted         = 1 << 7,
     };
 
     DEFINE_INLINE_TRACE() { visitor->trace(m_client); }
 
 private:
     explicit AutoplayExperimentHelper(Client*);
 
     // Register to receive position updates, if we haven't already.  If we
     // have, then this does nothing.
     void registerForPositionUpdatesIfNeeded();
@@ skipping 48 matching lines @@
     }
 
     Mode fromString(const String& mode);
 
     void recordAutoplayMetric(AutoplayMetrics);
 
     // Could stopping at this point be considered a bailout of playback?
     // (as in, "The user really didn't want to play this").
     bool isBailout() const;
 
+    // Returns true if and only if the experiment requires some sort of viewport
+    // visibility check for autoplay.
+    bool requiresViewportVisibility() const;
+
     Member<Client> m_client;
 
     Mode m_mode;
 
     // Autoplay experiment state.
     // True if we've received a play() without a pause().
     bool m_playPending : 1;
 
     // Are we registered with the view for position updates?
     bool m_registeredWithLayoutObject : 1;
@@ skipping 35 matching lines @@
 inline AutoplayExperimentHelper::Mode& operator|=(AutoplayExperimentHelper::Mode& a,
     const AutoplayExperimentHelper::Mode& b)
 {
     a = static_cast<AutoplayExperimentHelper::Mode>(static_cast<int>(a) | static_cast<int>(b));
     return a;
 }
 
 } // namespace blink
 
 #endif // AutoplayExperimentHelper_h