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

Source/core/html/MediaController.cpp

Index: Source/core/html/MediaController.cpp
diff --git a/Source/core/html/MediaController.cpp b/Source/core/html/MediaController.cpp
index 4494b08fe95994a710ae4f9cb7bd65ae3993090b..8f22f4353c827c7445b31f27d3aee45197aed7d5 100644
--- a/Source/core/html/MediaController.cpp
+++ b/Source/core/html/MediaController.cpp
@@ -485,20 +485,50 @@ void MediaController::bringElementUpToSpeed(HTMLMediaElement* element)
     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;