Bug 1366434 - Part 1. Automatically repeat mask-mode and mask-composite to match the number of mask layers. r=heycam

To do this, we simply need to add them into nsRuleNode::FillAllBackgroundLists.
It's gecko only bug, stylist in stylo handle it correctly.

MozReview-Commit-ID: 6GkuMZnNEqt

--HG--
extra : rebase_source : f0460bc054fd4385c2218b71ebae69d6e5693bb3

layout/style/nsRuleNode.cpp

@@ -7296,6 +7296,12 @@ nsRuleNode::FillAllBackgroundLists(nsStyleImageLayers& aImage,
   FillImageLayerList(aImage.mLayers,
                      &nsStyleImageLayers::Layer::mSize,
                      aImage.mSizeCount, fillCount);
+  FillImageLayerList(aImage.mLayers,
+                     &nsStyleImageLayers::Layer::mMaskMode,
+                     aImage.mMaskModeCount, fillCount);
+  FillImageLayerList(aImage.mLayers,
+                     &nsStyleImageLayers::Layer::mComposite,
+                     aImage.mCompositeCount, fillCount);
 }
 
 const void*