Raise the loading priority of in-viewport images.

Source/core/rendering/RenderImage.cpp

Index: Source/core/rendering/RenderImage.cpp
diff --git a/Source/core/rendering/RenderImage.cpp b/Source/core/rendering/RenderImage.cpp
index 478152baa4656289960a39095b7efb4f81ea8e30..9824738237b2be11f470fa8e7ed73cad2e55af37 100644
--- a/Source/core/rendering/RenderImage.cpp
+++ b/Source/core/rendering/RenderImage.cpp
@@ -31,6 +31,8 @@
 #include "HTMLNames.h"
 #include "core/editing/FrameSelection.h"
 #include "core/fetch/ImageResource.h"
+#include "core/fetch/ResourceLoadPriorityOptimizer.h"
+#include "core/fetch/ResourceLoader.h"
 #include "core/html/HTMLAreaElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
@@ -573,6 +575,28 @@ void RenderImage::layout()
     updateInnerContentRect();
 }
 
+void RenderImage::didLayout(ResourceLoadPriorityOptimizer& optimizer)
+{
+    RenderReplaced::didLayout(optimizer);
+    updateImageLoadingPriority(optimizer);
+}
+
+void RenderImage::didScroll(ResourceLoadPriorityOptimizer& optimizer)
+{
+    RenderReplaced::didScroll(optimizer);
+    updateImageLoadingPriority(optimizer);
+}
+
+void RenderImage::updateImageLoadingPriority(ResourceLoadPriorityOptimizer& optimizer)
+{
+    if (m_imageResource->cachedImage()) {
+        LayoutRect objectBounds = absoluteContentBox();
+        LayoutRect viewBounds = viewRect();
+
+        optimizer.notifyImageResourceVisibility(m_imageResource->cachedImage(), viewBounds.intersects(objectBounds));

[eseidel, 2013/11/25 23:59:30]

Shouldn't we only do this if the cached image hasn't loaded?

[shatch, 2013/11/26 01:35:18]

Done.

+    }
+}
+
 void RenderImage::computeIntrinsicRatioInformation(FloatSize& intrinsicSize, double& intrinsicRatio, bool& isPercentageIntrinsicSize) const
 {
     RenderReplaced::computeIntrinsicRatioInformation(intrinsicSize, intrinsicRatio, isPercentageIntrinsicSize);