Bug 602072 - Ensure media play() overrides preload='none'. r=roc a=blocking2.0

content/html/content/src/nsHTMLMediaElement.cpp

@@ -831,9 +831,11 @@ static PRBool IsAutoplayEnabled()
 void nsHTMLMediaElement::UpdatePreloadAction()
 {
   PreloadAction nextAction = PRELOAD_UNDEFINED;
-  // If autoplay is set, we should always preload data, as we'll need it
-  // to play.
-  if (IsAutoplayEnabled() && HasAttr(kNameSpaceID_None, nsGkAtoms::autoplay)) {
+  // If autoplay is set, or we're playing, we should always preload data,
+  // as we'll need it to play.
+  if ((IsAutoplayEnabled() && HasAttr(kNameSpaceID_None, nsGkAtoms::autoplay)) ||
+      !mPaused)
+  {
     nextAction = nsHTMLMediaElement::PRELOAD_ENOUGH;
   } else {
     // Find the appropriate preload action by looking at the attribute.
@@ -1394,7 +1396,9 @@ NS_IMETHODIMP nsHTMLMediaElement::Play()
   mPaused = PR_FALSE;
   mAutoplaying = PR_FALSE;
   // We changed mPaused and mAutoplaying which can affect AddRemoveSelfReference
+  // and our preload status.
   AddRemoveSelfReference();
+  UpdatePreloadAction();
 
   return NS_OK;
 }

content/media/test/test_preload_actions.html

@@ -535,6 +535,27 @@ var tests = [
       v.src = test.name;
     },    
   },
+  {
+    // 18. On a preload='none' video, call play() before load algorithms's sync
+    // has run, the play() call should override preload='none'.
+    ended:
+    function(e) {
+      ok(true, "(18) Got playback ended.");
+      var v = e.target;
+      v._finished = true;
+      maybeFinish(v, 18);
+    },
+    
+    setup:
+    function(v) {
+      v.addEventListener("ended", this.ended, false);
+      v._finished = false;
+      v.preload = "none";
+      v.src = test.name; // Schedules async section to continue load algorithm.
+      document.body.appendChild(v);
+      v.play(); // Should cause preload:none to be overridden.
+    },  
+    }
 ];
 
 function startTest(test, token) {