Fire load event for an image even if it was the last image we loaded successfully.

Source/core/loader/ImageLoader.cpp

Index: Source/core/loader/ImageLoader.cpp
diff --git a/Source/core/loader/ImageLoader.cpp b/Source/core/loader/ImageLoader.cpp
index 3c0d8b679fdac3776145ae9c6e980eae03d51343..91f5cd67bbaf7dc3d8d21c57e78de7c0890ae84e 100644
--- a/Source/core/loader/ImageLoader.cpp
+++ b/Source/core/loader/ImageLoader.cpp
@@ -289,8 +289,11 @@ void ImageLoader::doUpdateFromElement(BypassMainWorldBehavior bypassBehavior, Up
     }
 
     ImageResource* oldImage = m_image.get();
-    if (newImage != oldImage) {
-        sourceImageChanged();
+    if (updateBehavior == UpdateSizeChanged && m_element->layoutObject() && m_element->layoutObject()->isImage() && newImage == oldImage) {

[Yoav Weiss, 2015/04/02 07:52:10]

Hmm, I'm not sure that's the cleanest way to do that. The UpdateSizeChanged
behavior is there to update the image intrinsic size as a result of environment
changes. If that triggers onload in your test cases, I suspect it's a
side-effect :|

[rhogan, 2015/04/02 18:15:16]

It's not material for the test cases added by my CL, but there is coverage in
LayoutTests for the case where the viewport changes and srcset resizes the image
but doesn't select a new one. In that situation the spec tells me I don't want
to trigger a load event so that's what I'm doing here. 

+        toLayoutImage(m_element->layoutObject())->intrinsicSizeChanged();
+    } else {
+        if (newImage != oldImage)
+            sourceImageChanged();
 
         if (m_hasPendingLoadEvent) {
             loadEventSender().cancelEvent(this);
@@ -318,8 +321,6 @@ void ImageLoader::doUpdateFromElement(BypassMainWorldBehavior bypassBehavior, Up
 
         if (oldImage)
             oldImage->removeClient(this);

[Jimmy Jo, 2016/04/28 13:02:33]

I have a question.
If newImage and oldImage are equal, is this line same
newImage->removeClient(this)?

-    } else if (updateBehavior == UpdateSizeChanged && m_element->layoutObject() && m_element->layoutObject()->isImage()) {
-        toLayoutImage(m_element->layoutObject())->intrinsicSizeChanged();
     }
 
     if (LayoutImageResource* imageResource = layoutImageResource())