Don't use TransformMatrix in CommonLayerAttributes. (bug 1332567 part 2, r=mattwoodrow)

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -288,7 +288,7 @@ LayerTransactionParent::RecvUpdate(const TransactionInfo& aInfo,
       layer->SetOpacity(common.opacity());
       layer->SetClipRect(common.useClipRect() ? Some(common.clipRect()) : Nothing());
       layer->SetScrolledClip(common.scrolledClip());
-      layer->SetBaseTransform(common.transform().value());
+      layer->SetBaseTransform(common.transform());
       layer->SetTransformIsPerspective(common.transformIsPerspective());
       layer->SetPostScale(common.postXScale(), common.postYScale());
       layer->SetIsFixedPosition(common.isFixedPosition());

gfx/layers/ipc/LayersMessages.ipdlh

@@ -235,7 +235,7 @@ struct CommonLayerAttributes {
   IntRect layerBounds;
   LayerIntRegion visibleRegion;
   EventRegions eventRegions;
-  TransformMatrix transform;
+  Matrix4x4 transform;
   bool transformIsPerspective;
   float postXScale;
   float postYScale;