Bug 1246521: P1. Add MediaDecoderOwner::HasError method. r=gerald

dom/html/HTMLMediaElement.cpp

@@ -3494,6 +3494,11 @@ void HTMLMediaElement::DecodeError()
   }
 }
 
+bool HTMLMediaElement::HasError() const
+{
+  return GetError();
+}
+
 void HTMLMediaElement::LoadAborted()
 {
   Error(nsIDOMMediaError::MEDIA_ERR_ABORTED);

dom/html/HTMLMediaElement.h

@@ -177,6 +177,9 @@ public:
   // resource has a decode error during metadata loading or decoding.
   virtual void DecodeError() final override;
 
+  // Return true if error attribute is not null.
+  virtual bool HasError() const final override;
+
   // Called by the video decoder object, on the main thread, when the
   // resource load has been cancelled.
   virtual void LoadAborted() final override;

dom/media/MediaDecoderOwner.h

@@ -64,6 +64,9 @@ public:
   // resource has a decode error during metadata loading or decoding.
   virtual void DecodeError() = 0;
 
+  // Return true if media element error attribute is not null.
+  virtual bool HasError() const = 0;
+
   // Called by the video decoder object, on the main thread, when the
   // resource load has been cancelled.
   virtual void LoadAborted() = 0;

dom/media/gtest/MockMediaDecoderOwner.h

@@ -25,6 +25,7 @@ public:
   }
   void NetworkError() override {}
   void DecodeError() override {}
+  bool HasError() const override { return false; }
   void LoadAborted() override {}
   void PlaybackEnded() override {}
   void SeekStarted() override {}