Include viewport visibility checks for autoplay experiment.

LayoutTests/media/video-autoplay-experiment-modes.html

Index: LayoutTests/media/video-autoplay-experiment-modes.html
diff --git a/LayoutTests/media/video-autoplay-experiment-modes.html b/LayoutTests/media/video-autoplay-experiment-modes.html
index 41042561431443708c69e06abc316dfc2b988e5a..7b8fcb269f85b60e36bc8c55270a3560dfa4bd07 100644
--- a/LayoutTests/media/video-autoplay-experiment-modes.html
+++ b/LayoutTests/media/video-autoplay-experiment-modes.html
@@ -12,9 +12,10 @@
   Flags  - autoplay experiment setting being tested.
                a      - "foraudio"
                v      - "forvideo"
+               V      - "ifviewport"
                M      - "ifmuted"
                p      - "playmuted"
-               For example, EM means "enabled-ifmuted".
+               For example, vM means '-forvideo-ifmuted".
                This test does not check -ifmobile since that check always
                fails outside of android.
   Type   - audio or video element?
@@ -28,8 +29,15 @@
                none - media is not muted.
                attr - muted attribute is set on the element.
                js   - muted property is set after media is ready to play.
+  View   - is media in viewport?
+               onscreen  - element starts out onscreen.
+               scroll    - element starts offscreen, scrolled into view once
+                           it is ready to play.
+               offscreen - element starts out offscreen and stays offscreen.
 
   == Test Outputs ==
+  Early?  - did playback start before element was scrolled onscreen?  For
+            tests in which View!=scroll, this is reported as "-".
   Played? - did playback start by the conclusion of the test?
   Muted?  - was the media muted?  If the media didn't play, then this is
             reported as "-".
@@ -42,6 +50,8 @@
 <td>Type</td>
 <td>Play w/</td>
 <td>Mute</td>
+<td>View</td>
+<td>Early?</td>
 <td>Played?</td>
 <td>Muted?</td>
 </tr>
@@ -55,13 +65,19 @@ var configNumber = 0;
 
 var mediaFile = findMediaFile("video", "content/test");
 var onscreenParent = document.createElement("div");
+// The onscreen parent's height is also used to make sure that the off-screen
+// parent is, in fact, off-screen.
+onscreenParent.style.height="1000px";
 document.body.insertBefore(onscreenParent, document.body.firstChild);
+// Also create another root that's off the bottom of the window.
+var offscreenParent = document.createElement("div");
+document.body.appendChild(offscreenParent);
 
-function didPlaybackStart(video)
+function didPlaybackStart(element)
 {
-    // We say that the video started if it's not paused or if it played and
+    // We say that the element started if it's not paused or if it played and
     // already ended.
-    return !video.paused || video.ended;
+    return !element.paused || element.ended;
 }
 
 function addResultsRow(spec)
@@ -78,18 +94,19 @@ function addResultsRow(spec)
     var smallType = "";
     smallType += (type.indexOf("-forvideo")>-1)?"v":"";
     smallType += (type.indexOf("-foraudio")>-1)?"a":"";
+    smallType += (type.indexOf("-ifviewport")>-1)?"V":"";
     smallType += (type.indexOf("-ifmuted")>-1)?"M":"";
     smallType += (type.indexOf("-playmuted")>-1)?"p":"";
     row.insertCell(-1).innerText = smallType;
 
     // Add remaining fields.
-    var fields = [ "elementType", "autoplayType", "mutedType", "played",
-        "muted"];
+    var fields = [ "elementType", "autoplayType", "mutedType", "visType",
+        "playedEarly", "played", "muted"];
     for(idx in fields)
         row.insertCell(-1).innerText = spec[fields[idx]].substring(0,7);
 }
 
-function configureVideoViaScript(element, spec)
+function configureElementViaScript(element, spec)
 {
     if (spec.mutedType == "js")
         element.muted = true;
@@ -113,6 +130,9 @@ function checkElementStatus(element)
     addResultsRow(element.spec);
     element.parentElement.removeChild(element);
 
+    // Scroll back to the top, in case this was a scrolling test.
+    onscreenParent.scrollIntoView();
+
     queueNextExperiment();
 }
 
@@ -122,8 +142,13 @@ function runOneConfig(spec)
 
     // Create, configure, and attach a media element.
     var element = document.createElement(spec.elementType);
+    element.setAttribute("controls", "true");
 
-    onscreenParent.appendChild(element);
+    // Pick whether the element will be visible when canPlayThrough.
+    if (spec.visType == "onscreen")
+        onscreenParent.appendChild(element);
+    else
+        offscreenParent.appendChild(element);
 
     // Set any attributes before canPlayThrough.
     if (spec.mutedType == "attr")
@@ -131,6 +156,8 @@ function runOneConfig(spec)
     if (spec.autoplayType == "attr")
         element.setAttribute("autoplay", "true");
 
+    spec.playedEarly = "-";
+
     // Record the spec in the element, so that we can display the
     // results later.
     element.spec = spec;
@@ -140,10 +167,28 @@ function runOneConfig(spec)
     element.addEventListener("canplaythrough", function()
     {
         // Now that we can play, if we're supposed to play / mute via js do so.
-        configureVideoViaScript(element, spec);
-
-        // Record the results.
-        checkElementStatus(element);
+        configureElementViaScript(element, spec);
+
+        // If we're supposed to scroll the item onscreen after it is ready to
+        // play, then do so now.
+        if(spec.visType == "scroll") {
+            // Record the play state here, too, before we scroll.
+            spec.playedEarly = didPlaybackStart(element) ? "yes" : "no";
+
+            // We are supposed to scroll the player into view.
+            element.scrollIntoView(true);
+            // We cause two visibility checks.  The first notices the scroll,
+            // while the second notices that scrolling has stopped.
+            // It would be nicer to trigger location polling here, but that
+            // can take ~second to notice that scrolling is stopped.
+            window.internals.triggerAutoplayViewportCheck(element);
+            window.internals.triggerAutoplayViewportCheck(element);
+            // Once those are return, the state should be correct.
+            checkElementStatus(element, spec);
+        } else {
+            // Record the results immediately.
+            checkElementStatus(element, spec);
+        }
     });
 
     // Set the source, which will eventually lead to canPlayThrough.
@@ -153,13 +198,16 @@ function runOneConfig(spec)
 var experimentTypes = [
     "none",
     "enabled-forvideo",
-    "enabled-forvideo-ifmuted",
-    "enabled-forvideo-playmuted",
+    "enabled-forvideo-ifviewport",
+    "enabled-forvideo-ifviewport-ifmuted",
+    "enabled-forvideo-ifviewport-playmuted",
     "enabled-foraudio",
+    "enabled-foraudio-ifviewport",
 ];
 var elementTypes = ["video", "audio"];
 var autoplayTypes = ["none", "attr", "play()"];
 var mutedTypes = ["none", "attr", "js"];
+var visTypes = ["onscreen", "scroll", "offscreen"];
 
 function runNextConfig()
 {
@@ -176,6 +224,8 @@ function runNextConfig()
     exp = Math.floor(exp / autoplayTypes.length);
     spec.mutedType = mutedTypes[exp % mutedTypes.length];
     exp = Math.floor(exp / mutedTypes.length);
+    spec.visType = visTypes[exp % visTypes.length];
+    exp = Math.floor(exp / visTypes.length);
     spec.experimentNumber = configNumber;
 
     // exp>0 here indicates that we've wrapped around.
@@ -187,7 +237,26 @@ function runNextConfig()
 
     // To keep the test fast, skip a few combinations.
     var skip = false;
-    if (spec.experimentType.indexOf("-ifmuted") == -1 && spec.mutedType != "none")
+    var mismatched =(spec.elementType == "video"
+        && spec.experimentType.indexOf("-foraudio") > -1)
+        || (spec.elementType == "audio"
+        && spec.experimentType.indexOf("-forvideo") > -1);
+
+    if (spec.autoplayType == "none" && spec.visType != 'onscreen')
+        skip = true;
+    else if (spec.experimentType.indexOf("-ifmuted") > -1 && spec.visType != "onscreen")
+        skip = true;
+    else if (spec.visType == "offscreen" && spec.autoplayType != "attr")
+        skip = true;
+    else if (spec.experimentType.indexOf("-ifmuted") == -1 && spec.mutedType != "none")
+        skip = true;
+    else if (spec.elementType == "audio" && spec.mutedType != "none")
+        skip = true;
+    else if (spec.elementType == "audio" && spec.visType != "scroll")
+        skip = true;
+    else if (mismatched && spec.visType !="onscreen")
+        skip = true;
+    else if (mismatched && spec.autoplayType != "attr")
         skip = true;
 
     if (skip)