Bug 1440555 - P1: Allow setVisible to take effect before decoder creation. r=cpearce

MozReview-Commit-ID: GSNM6esm0fW

--HG--
extra : rebase_source : 89a9836a48a93f7dfc5ce78bc6fd8b2c11da9c0e

dom/html/HTMLMediaElement.cpp

@@ -1645,11 +1645,10 @@ HTMLMediaElement::MozDumpDebugInfo()
 void
 HTMLMediaElement::SetVisible(bool aVisible)
 {
-  if (!mDecoder) {
-    return;
-  }
-
+  mForcedHidden = !aVisible;
+  if (mDecoder) {
     mDecoder->SetForcedHidden(!aVisible);
+  }
 }
 
 already_AddRefed<layers::Image>
@@ -3880,6 +3879,7 @@ HTMLMediaElement::HTMLMediaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNo
     mFirstFrameLoaded(false),
     mDefaultPlaybackStartPosition(0.0),
     mHasSuspendTaint(false),
+    mForcedHidden(false),
     mMediaTracksConstructed(false),
     mVisibilityState(Visibility::UNTRACKED),
     mErrorSink(new ErrorSink(this)),
@@ -7331,6 +7331,9 @@ HTMLMediaElement::SetDecoder(MediaDecoder* aDecoder)
   }
   mDecoder = aDecoder;
   DDLINKCHILD("decoder", mDecoder.get());
+  if (mDecoder && mForcedHidden) {
+    mDecoder->SetForcedHidden(mForcedHidden);
+  }
 }
 
 float

dom/html/HTMLMediaElement.h

@@ -1821,6 +1821,10 @@ private:
   // participate in video decoder suspending.
   bool mHasSuspendTaint;
 
+  // True if media element has been forced into being considered 'hidden'.
+  // For use by mochitests. Enabling pref "media.test.video-suspend"
+  bool mForcedHidden;
+
   // True if audio tracks and video tracks are constructed and added into the
   // track list, false if all tracks are removed from the track list.
   bool mMediaTracksConstructed;

dom/media/MediaDecoderStateMachine.cpp

@@ -3080,6 +3080,11 @@ void MediaDecoderStateMachine::SetVideoDecodeModeInternal(VideoDecodeMode aMode)
 {
   MOZ_ASSERT(OnTaskQueue());
 
+  LOG("SetVideoDecodeModeInternal(), VideoDecodeMode=(%s->%s), mVideoDecodeSuspended=%c",
+      mVideoDecodeMode == VideoDecodeMode::Normal ? "Normal" : "Suspend",
+      aMode == VideoDecodeMode::Normal ? "Normal" : "Suspend",
+      mVideoDecodeSuspended ? 'T' : 'F');
+
   // Should not suspend decoding if we don't turn on the pref.
   if (!MediaPrefs::MDSMSuspendBackgroundVideoEnabled() &&
       aMode == VideoDecodeMode::Suspend) {
@@ -3092,11 +3097,6 @@ void MediaDecoderStateMachine::SetVideoDecodeModeInternal(VideoDecodeMode aMode)
     return;
   }
 
-  LOG("SetVideoDecodeModeInternal(), VideoDecodeMode=(%s->%s), mVideoDecodeSuspended=%c",
-      mVideoDecodeMode == VideoDecodeMode::Normal ? "Normal" : "Suspend",
-      aMode == VideoDecodeMode::Normal ? "Normal" : "Suspend",
-      mVideoDecodeSuspended ? 'T' : 'F');
-
   // Set new video decode mode.
   mVideoDecodeMode = aMode;