Implement the activation behavior of media elements (click to play/pause)

Source/core/html/MediaController.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 467 matching lines @@
 {
     ASSERT(element);
     ASSERT(m_mediaElements.contains(element));
 
     // When the user agent is to bring a media element up to speed with its new media controller,
     // it must seek that media element to the MediaController's media controller position relative
     // to the media element's timeline.
     element->seek(currentTime(), IGNORE_EXCEPTION);
 }
 
+bool MediaController::isRestrained() const
+{
+    ASSERT(!m_mediaElements.isEmpty());
+
+    // A MediaController is a restrained media controller if the MediaController is a playing media
+    // controller,
+    if (m_paused)
+        return false;
+
+    bool allPaused = true;
+    for (size_t index = 0; index < m_mediaElements.size(); ++index) {
+        HTMLMediaElement* element = m_mediaElements[index];
+
+        // and none of its slaved media elements are blocked media elements,
+        if (element->isBlocked())
+            return false;
+
+        // but either at least one of its slaved media elements whose autoplaying flag is true still
+        // has its paused attribute set to true,
+        if (element->isAutoplaying() && element->paused())
+            return true;
+
+        if (!element->paused())
+            allPaused = false;

[acolwell GONE FROM CHROMIUM, 2014/03/21 23:30:12]

I think you can just return false here and return true at the end of the
function.

[philipj_slow, 2014/03/23 03:42:49]

I had difficulties parsing the spec definition and even filed a bug:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=25105

I concluded that the condition should be "playing && noneBlocked &&
(anyAutoplayingAndPaused || allPaused)" but actually still failed to implement
that correctly, and failed to catch it with my tests.

I've fix this and added tests until I couldn't change any part of the function
without causing a failure.

+    }
+
+    // or, all of its slaved media elements have their paused attribute set to true.
+    return allPaused;
+}
+
 bool MediaController::isBlocked() const
 {
+    ASSERT(!m_mediaElements.isEmpty());
+
     // A MediaController is a blocked media controller if the MediaController is a paused media
     // controller,
     if (m_paused)
         return true;
 
-    if (m_mediaElements.isEmpty())
-        return false;
-
     bool allPaused = true;
     for (size_t index = 0; index < m_mediaElements.size(); ++index) {
         HTMLMediaElement* element = m_mediaElements[index];
-        //  or if any of its slaved media elements are blocked media elements,
+
+        // or if any of its slaved media elements are blocked media elements,
         if (element->isBlocked())
             return true;
 
         // or if any of its slaved media elements whose autoplaying flag is true still have their
         // paused attribute set to true,
         if (element->isAutoplaying() && element->paused())
             return true;
 
         if (!element->paused())
             allPaused = false;
@@ skipping 107 matching lines @@
 {
     double now = WTF::currentTime();
     double timedelta = now - m_previousTimeupdateTime;
 
     if (timedelta < maxTimeupdateEventFrequency)
         return;
 
     scheduleEvent(EventTypeNames::timeupdate);
     m_previousTimeupdateTime = now;
 }