Fix Resource Priorities and Scheduling (Blink Side)

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/frame/Settings.h"
 #include "core/layout/LayoutObject.h"
 #include "platform/TraceEvent.h"
 
 #include "wtf/Vector.h"
 
 namespace blink {
 
 ResourceLoadPriorityOptimizer* ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()
 {
     DEFINE_STATIC_LOCAL(ResourceLoadPriorityOptimizer, s_renderLoadOptimizer, ());
     return &s_renderLoadOptimizer;
 }
 
 ResourceLoadPriorityOptimizer::ResourceAndVisibility::ResourceAndVisibility(ImageResource* image, VisibilityStatus visibilityStatus, uint32_t screenArea)
     : imageResource(image)
     , status(visibilityStatus)
     , screenArea(screenArea)
 {
 }
 
 ResourceLoadPriorityOptimizer::ResourceAndVisibility::~ResourceAndVisibility()
 {
 }
 
 ResourceLoadPriorityOptimizer::ResourceLoadPriorityOptimizer()
+    : m_retrievedSettings(false)
+    , m_increaseFetchPriorities(false)
 {
 }
 
 ResourceLoadPriorityOptimizer::~ResourceLoadPriorityOptimizer()
 {
 }
 
 void ResourceLoadPriorityOptimizer::addLayoutObject(LayoutObject* layoutObject)
 {
+    if (!m_retrievedSettings) {
+        // The list of image resources is populated by the layout objects in
+        // updateAllImageResourcePriorities so it is safe to only check the
+        // setting when the first layout object is added.  It is impossible to
+        // have images to update without having first populated at least one
+        // layout object.
+        m_increaseFetchPriorities = layoutObject->document().settings()->fetchIncreasePriorities();
+        m_retrievedSettings = true;
+    }
     m_objects.add(layoutObject);
     layoutObject->setHasPendingResourceUpdate(true);
 }
 
 void ResourceLoadPriorityOptimizer::removeLayoutObject(LayoutObject* layoutObject)
 {
     if (!layoutObject->hasPendingResourceUpdate())
         return;
     m_objects.remove(layoutObject);
     layoutObject->setHasPendingResourceUpdate(false);
@@ skipping 14 matching lines @@
 
     updateImageResourcesWithLoadPriority();
 }
 
 void ResourceLoadPriorityOptimizer::updateImageResourcesWithLoadPriority()
 {
     for (const auto& resource : m_imageResources) {
         ResourceLoadPriority priority = resource.value->status == Visible ?
             ResourceLoadPriorityLow : ResourceLoadPriorityVeryLow;
 
+        if (m_increaseFetchPriorities) {
+            priority = resource.value->status == Visible ?
+                ResourceLoadPriorityHigh : ResourceLoadPriorityLow;
+        }
+
         if (priority != resource.value->imageResource->resourceRequest().priority()) {
             resource.value->imageResource->mutableResourceRequest().setPriority(priority, resource.value->screenArea);
             resource.value->imageResource->didChangePriority(priority, resource.value->screenArea);
         }
     }
     m_imageResources.clear();
 }
 
 void ResourceLoadPriorityOptimizer::notifyImageResourceVisibility(ImageResource* img, VisibilityStatus status, const LayoutRect& screenRect)
 {
     if (!img || img->isLoaded())
         return;
 
     int screenArea = 0;
     if (!screenRect.isEmpty() && status == Visible)
         screenArea += static_cast<uint32_t>(screenRect.width() * screenRect.height());
 
     ImageResourceMap::AddResult result = m_imageResources.add(img->identifier(), adoptPtr(new ResourceAndVisibility(img, status, screenArea)));
     if (!result.isNewEntry && status == Visible) {
         result.storedValue->value->status = Visible;
         result.storedValue->value->screenArea += screenArea;
     }
 }
 
 }