Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

Source/core/fetch/ResourceLoadPriorityOptimizer.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 12 matching lines @@
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/fetch/ResourceLoadPriorityOptimizer.h"
+#include "core/rendering/RenderObject.h"
+
+#include "wtf/Vector.h"
 
 namespace WebCore {
 
+ResourceLoadPriorityOptimizer* ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()
+{
+    DEFINE_STATIC_LOCAL(ResourceLoadPriorityOptimizer, s_renderLoadOptimizer, ());
+    return &s_renderLoadOptimizer;
+}
+
 ResourceLoadPriorityOptimizer::ResourceAndVisibility::ResourceAndVisibility(ImageResource* image, VisibilityStatus v)
     : imageResource(image)
     , status(v)
 {
 }
 
 ResourceLoadPriorityOptimizer::ResourceAndVisibility::~ResourceAndVisibility()
 {
 }
 
 ResourceLoadPriorityOptimizer::ResourceLoadPriorityOptimizer()
 {
 }
 
 ResourceLoadPriorityOptimizer::~ResourceLoadPriorityOptimizer()
 {
+}
+
+void ResourceLoadPriorityOptimizer::addRenderObject(RenderObject* renderer)
+{
+    m_objects.add(renderer);
+    renderer->setHasPendingResourceUpdate(true);
+}
+
+void ResourceLoadPriorityOptimizer::removeRenderObject(RenderObject* renderer)
+{
+    if (!renderer->hasPendingResourceUpdate())
+        return;
+    m_objects.remove(renderer);
+    renderer->setHasPendingResourceUpdate(false);
+}
+
+void ResourceLoadPriorityOptimizer::updateAllImageResourcePriorities()
+{
+    m_imageResources.clear();
+
+    Vector<RenderObject*> objectsToRemove;
+    for (RenderObjectSet::iterator it = m_objects.begin(); it != m_objects.end(); ++it) {
+        RenderObject* obj = *it;
+        if (!obj->updateImageLoadingPriorities()) {
+            objectsToRemove.append(obj);
+        }
+    }
+
+    for (Vector<RenderObject*>::iterator it = objectsToRemove.begin(); it != objectsToRemove.end(); ++it)
+        m_objects.remove(*it);
+
     updateImageResourcesWithLoadPriority();
 }
 
 void ResourceLoadPriorityOptimizer::updateImageResourcesWithLoadPriority()
 {
     for (ImageResourceMap::iterator it = m_imageResources.begin(); it != m_imageResources.end(); ++it) {
         ResourceLoadPriority priority = it->value->status == Visible ?
             ResourceLoadPriorityLow : ResourceLoadPriorityVeryLow;
 
         if (priority != it->value->imageResource->resourceRequest().priority()) {
             it->value->imageResource->resourceRequest().setPriority(priority);
             it->value->imageResource->didChangePriority(priority);
         }
     }
     m_imageResources.clear();
 }
 
 void ResourceLoadPriorityOptimizer::notifyImageResourceVisibility(ImageResource* img, VisibilityStatus status)
 {
     if (!img || img->isLoaded())
         return;
 
     ImageResourceMap::AddResult result = m_imageResources.add(img->identifier(), adoptPtr(new ResourceAndVisibility(img, status)));
     if (!result.isNewEntry && status == Visible)
         result.iterator->value->status = status;
 }
 
 }