cc: Start using raster/eviction iterators in tile manager

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 94c3d201639d0dd90a29545ba18ca067f43edd8a..bed02f2fa633f578bc7c361a0d42a4a8c6fba37b 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -1363,6 +1363,20 @@ PictureLayerImpl::LayerRasterTileIterator::operator bool() const {
   return layer_ && static_cast<size_t>(current_stage_) < arraysize(stages_);
 }
 
+bool PictureLayerImpl::LayerRasterTileIterator::HasTilesRequiredForActivation()
+    const {
+  if (!*this)
+    return false;
+
+  int stage_count = arraysize(stages_);
+  for (int stage = current_stage_; stage < stage_count; ++stage) {
+    IteratorType index = stages_[stage].iterator_type;
+    if (iterators_[index].HasTilesRequiredForActivation())
+      return true;
+  }
+  return false;
+}
+
 PictureLayerImpl::LayerRasterTileIterator&
 PictureLayerImpl::LayerRasterTileIterator::
 operator++() {