Add a new API for testing animated images

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 494 matching lines @@
 
     Image* imageData = resource->image();
     if (!imageData->isBitmapImage()) {
         exceptionState.throwDOMException(InvalidAccessError, "The image resource is not a BitmapImage type.");
         return;
     }
 
     imageData->advanceTime(deltaTimeInSeconds);
 }
 
+void Internals::advanceImageAnimation(Element* image, ExceptionState& exceptionState)
+{
+    ASSERT(image);
+
+    ImageResource* resource = nullptr;
+    if (isHTMLImageElement(*image)) {
+        resource = toHTMLImageElement(*image).cachedImage();
+    } else if (isSVGImageElement(*image)) {
+        resource = toSVGImageElement(*image).cachedImage();
+    } else {
+        exceptionState.throwDOMException(InvalidAccessError, "The element provided is not a image element.");
+        return;
+    }
+
+    if (!resource || !resource->hasImage()) {
+        exceptionState.throwDOMException(InvalidAccessError, "The image resource is not available.");
+        return;
+    }
+
+    Image* imageData = resource->image();
+    imageData->advanceAnimationForTesting();
+}
+
 bool Internals::hasShadowInsertionPoint(const Node* root, ExceptionState& exceptionState) const
 {
     ASSERT(root);
     if (!root->isShadowRoot()) {
         exceptionState.throwDOMException(InvalidAccessError, "The node argument is not a shadow root.");
         return false;
     }
     return toShadowRoot(root)->containsShadowElements();
 }
 
@@ skipping 1967 matching lines @@
 
     return animator->setScrollbarsVisibleForTesting(visible);
 }
 
 void Internals::forceRestrictIFramePermissions()
 {
     RuntimeEnabledFeatures::setRestrictIFramePermissionsEnabled(true);
 }
 
 } // namespace blink