Bug 1112972 (Part 1) - Minor refactoring to prepare for MultipartImage. r=tn

image/src/ImageWrapper.h

@@ -65,7 +65,7 @@ protected:
   explicit ImageWrapper(Image* aInnerImage)
     : mInnerImage(aInnerImage)
   {
-    NS_ABORT_IF_FALSE(aInnerImage, "Cannot wrap a null image");
+    MOZ_ASSERT(aInnerImage, "Need an image to wrap");
   }
 
   virtual ~ImageWrapper() { }
@@ -73,7 +73,13 @@ protected:
   /**
    * Returns a weak reference to the inner image wrapped by this ImageWrapper.
    */
-  Image* InnerImage() { return mInnerImage.get(); }
+  Image* InnerImage() const { return mInnerImage.get(); }
+
+  void SetInnerImage(Image* aInnerImage)
+  {
+    MOZ_ASSERT(aInnerImage, "Need an image to wrap");
+    mInnerImage = aInnerImage;
+  }
 
 private:
   nsRefPtr<Image> mInnerImage;

image/src/ProgressTracker.cpp

@@ -29,10 +29,10 @@ ProgressTrackerInit::ProgressTrackerInit(Image* aImage,
 
   if (aTracker) {
     mTracker = aTracker;
-    mTracker->SetImage(aImage);
   } else {
-    mTracker = new ProgressTracker(aImage);
+    mTracker = new ProgressTracker();
   }
+  mTracker->SetImage(aImage);
   aImage->SetProgressTracker(mTracker);
   MOZ_ASSERT(mTracker);
 }
@@ -425,8 +425,7 @@ ProgressTracker::SyncNotify(IProgressObserver* aObserver)
 }
 
 void
-ProgressTracker::EmulateRequestFinished(IProgressObserver* aObserver,
-                                        nsresult aStatus)
+ProgressTracker::EmulateRequestFinished(IProgressObserver* aObserver)
 {
   MOZ_ASSERT(NS_IsMainThread(),
              "SyncNotifyState and mObservers are not threadsafe");
@@ -448,9 +447,8 @@ ProgressTracker::AddObserver(IProgressObserver* aObserver)
   mObservers.AppendElementUnlessExists(aObserver);
 }
 
-// XXX - The last argument should go away.
 bool
-ProgressTracker::RemoveObserver(IProgressObserver* aObserver, nsresult aStatus)
+ProgressTracker::RemoveObserver(IProgressObserver* aObserver)
 {
   MOZ_ASSERT(NS_IsMainThread());
 
@@ -460,7 +458,7 @@ ProgressTracker::RemoveObserver(IProgressObserver* aObserver, nsresult aStatus)
   // Observers can get confused if they don't get all the proper teardown
   // notifications. Part ways on good terms.
   if (removed && !aObserver->NotificationsDeferred()) {
-    EmulateRequestFinished(aObserver, aStatus);
+    EmulateRequestFinished(aObserver);
   }
 
   // Make sure we don't give callbacks to an observer that isn't interested in

image/src/ProgressTracker.h

@@ -77,11 +77,8 @@ public:
   MOZ_DECLARE_REFCOUNTED_TYPENAME(ProgressTracker)
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ProgressTracker)
 
-  // aImage is the image that will be passed to the observers in SyncNotify()
-  // and EmulateRequestFinished(), and must be alive as long as this instance
-  // is, because we hold a weak reference to it.
-  explicit ProgressTracker(Image* aImage)
-    : mImage(aImage)
+  ProgressTracker()
+    : mImage(nullptr)
     , mProgress(NoProgress)
   { }
 
@@ -159,7 +156,7 @@ public:
   // We manage a set of observers that are using an image and thus concerned
   // with its loading progress. Weak pointers.
   void AddObserver(IProgressObserver* aObserver);
-  bool RemoveObserver(IProgressObserver* aObserver, nsresult aStatus);
+  bool RemoveObserver(IProgressObserver* aObserver);
   size_t ObserverCount() const {
     MOZ_ASSERT(NS_IsMainThread(), "Use mObservers on main thread only");
     return mObservers.Length();
@@ -195,7 +192,7 @@ private:
   // Send some notifications that would be necessary to make |aObserver| believe
   // the request is finished downloading and decoding.  We only send
   // FLAG_LOAD_COMPLETE and FLAG_ONLOAD_UNBLOCKED, and only if necessary.
-  void EmulateRequestFinished(IProgressObserver* aObserver, nsresult aStatus);
+  void EmulateRequestFinished(IProgressObserver* aObserver);
 
   // Main thread only because it deals with the observer service.
   void FireFailureNotification();

image/src/imgRequest.cpp

@@ -62,7 +62,7 @@ NS_IMPL_ISUPPORTS(imgRequest,
 
 imgRequest::imgRequest(imgLoader* aLoader)
  : mLoader(aLoader)
- , mProgressTracker(new ProgressTracker(nullptr))
+ , mProgressTracker(new ProgressTracker())
  , mValidator(nullptr)
  , mInnerWindowId(0)
  , mCORSMode(imgIRequest::CORS_NONE)
@@ -204,7 +204,7 @@ nsresult imgRequest::RemoveProxy(imgRequestProxy *proxy, nsresult aStatus)
   // before Cancel() returns, leaving the image in a different state then the
   // one it was in at this point.
   nsRefPtr<ProgressTracker> progressTracker = GetProgressTracker();
-  if (!progressTracker->RemoveObserver(proxy, aStatus))
+  if (!progressTracker->RemoveObserver(proxy))
     return NS_OK;
 
   if (progressTracker->ObserverCount() == 0) {
@@ -897,7 +897,7 @@ imgRequest::OnDataAvailable(nsIRequest *aRequest, nsISupports *ctxt,
         MOZ_ASSERT(mIsMultiPartChannel, "Resniffing a non-multipart image");
 
         // Initialize a new status tracker.
-        nsRefPtr<ProgressTracker> freshTracker = new ProgressTracker(nullptr);
+        nsRefPtr<ProgressTracker> freshTracker = new ProgressTracker();
         freshTracker->SetIsMultipart();
 
         // Replace the old status tracker with it.