Bug 1420488 - part1 : bless media if media has started playing before. r=jwwang

If the media has started playing before, bless it and it would always be allowed
to autoplay.

MozReview-Commit-ID: 4GqMARLXULU

--HG--
extra : rebase_source : 2fdb3937156147755f8e387b1d84311ae1d37ce4

dom/html/HTMLMediaElement.cpp

@@ -1979,12 +1979,12 @@ void HTMLMediaElement::DoLoad()
     return;
   }
 
-  // Detect if user has interacted with element so that play will not be
-  // blocked when initiated by a script. This enables sites to capture user
-  // intent to play by calling load() in the click handler of a "catalog
-  // view" of a gallery of videos.
   if (EventStateManager::IsHandlingUserInput()) {
-    mHasUserInteractedLoadOrSeek = true;
+    // Detect if user has interacted with element so that play will not be
+    // blocked when initiated by a script. This enables sites to capture user
+    // intent to play by calling load() in the click handler of a "catalog
+    // view" of a gallery of videos.
+    mIsBlessed = true;
     // Mark the channel as urgent-start when autopaly so that it will play the
     // media from src after loading enough resource.
     if (HasAttr(kNameSpaceID_None, nsGkAtoms::autoplay)) {
@@ -2757,7 +2757,7 @@ HTMLMediaElement::Seek(double aTime,
   // Detect if user has interacted with element by seeking so that
   // play will not be blocked when initiated by a script.
   if (EventStateManager::IsHandlingUserInput()) {
-    mHasUserInteractedLoadOrSeek = true;
+    mIsBlessed = true;
   }
 
   StopSuspendingAfterFirstFrame();
@@ -4043,7 +4043,6 @@ HTMLMediaElement::HTMLMediaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNo
     mIsEncrypted(false),
     mWaitingForKey(NOT_WAITING_FOR_KEY),
     mDisableVideo(false),
-    mHasUserInteractedLoadOrSeek(false),
     mFirstFrameLoaded(false),
     mDefaultPlaybackStartPosition(0.0),
     mHasSuspendTaint(false),
@@ -4286,6 +4285,9 @@ HTMLMediaElement::PlayInternal(ErrorResult& aRv)
   UpdatePreloadAction();
   UpdateSrcMediaStreamPlaying();
 
+  // once media start playing, we would always allow it to autoplay
+  mIsBlessed = true;
+
   // TODO: If the playback has ended, then the user agent must set
   // seek to the effective start.
 

dom/html/HTMLMediaElement.h

@@ -741,11 +741,9 @@ public:
 
   void NotifyCueDisplayStatesChanged();
 
-  bool GetAndClearHasUserInteractedLoadOrSeek()
+  bool IsBlessed() const
   {
-    bool result = mHasUserInteractedLoadOrSeek;
-    mHasUserInteractedLoadOrSeek = false;
-    return result;
+    return mIsBlessed;
   }
 
   // A method to check whether we are currently playing.
@@ -1785,9 +1783,9 @@ private:
   // Total time a video has (or would have) spent in video-decode-suspend mode.
   TimeDurationAccumulator mVideoDecodeSuspendTime;
 
-  // True if user has called load() or seek() via user input.
+  // True if user has called load(), seek() or element has started playing before.
   // It's *only* use for checking autoplay policy
-  bool mHasUserInteractedLoadOrSeek;
+  bool mIsBlessed = false;
 
   // True if the first frame has been successfully loaded.
   bool mFirstFrameLoaded;

dom/media/AutoplayPolicy.cpp

@@ -38,9 +38,8 @@ AutoplayPolicy::IsMediaElementAllowedToPlay(NotNull<HTMLMediaElement*> aElement)
 
   // TODO : this old way would be removed when user-gestures-needed becomes
   // as a default option to block autoplay.
-  // If user triggers load() or seek() before play(), we would also allow the
-  // following play().
-  return aElement->GetAndClearHasUserInteractedLoadOrSeek() ||
+  // If elelement is blessed, it would always be allowed to play().
+  return aElement->IsBlessed() ||
          EventStateManager::IsHandlingUserInput();
 }