Include viewport visibility checks for autoplay experiment.

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

Index: third_party/WebKit/Source/core/html/AutoplayExperimentConfig.h
diff --git a/third_party/WebKit/Source/core/html/AutoplayExperimentConfig.h b/third_party/WebKit/Source/core/html/AutoplayExperimentConfig.h
index e1dd6daa4ca8ae2d216aa7a2eb938f05be704f31..c32a62a9c94d78ece9e5dfc72a3d4d8c80e34c5a 100644
--- a/third_party/WebKit/Source/core/html/AutoplayExperimentConfig.h
+++ b/third_party/WebKit/Source/core/html/AutoplayExperimentConfig.h
@@ -14,25 +14,30 @@ namespace blink {
 class AutoplayExperimentConfig {
     public:
     // Experiment configuration bits.  These maybe combined.  For example,
-    // ForVideo|IfMuted will override the user gesture requirement for
-    // playing video that has no audio or is muted.  ForVideo, by itself,
+    // ForVideo|IfViewport will override the user gesture requirement for
+    // playing video that is visible in the viewport.  ForVideo, by itself,
     // will entirely override the user gesture requirement for all video
     // elements, but not for audio elements.
     enum Mode {
         // Do not enable the autoplay experiment.
-        Off        = 0,
+        Off           = 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
+        // the viewport.
+        IfViewport    = 1 << 3,
         // Restrict gestureless autoplay to audio-less or muted media.
-        IfMuted    = 1 << 2,
+        IfMuted       = 1 << 4,
         // Restrict gestureless autoplay to sites which contain the
         // viewport tag.
-        IfMobile   = 1 << 3,
+        IfMobile      = 1 << 5,
         // If gestureless autoplay is allowed, then mute the media before
         // starting to play.
-        PlayMuted  = 1 << 4,
+        PlayMuted     = 1 << 6,
     };
 
     static Mode fromString(const WTF::String& token);