cc: Change TileManager iterators to be queues.

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 05fc478370d1c1c50ac09d30ea31051e3409cedb..af12fb7a955b202ee5116f70dc5bbdd4a0ba533e 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -6700,5 +6700,49 @@ TEST_F(LayerTreeHostImplTest, ScrollAnimated) {
   EXPECT_EQ(NULL, host_impl_->CurrentlyScrollingLayer());
 }
 
+TEST_F(LayerTreeHostImplTest, GetPairedPictureLayerImplPairs) {
+  host_impl_->CreatePendingTree();
+  host_impl_->ActivateSyncTree();
+  host_impl_->CreatePendingTree();
+
+  LayerTreeImpl* active_tree = host_impl_->active_tree();
+  LayerTreeImpl* pending_tree = host_impl_->pending_tree();
+  EXPECT_NE(active_tree, pending_tree);
+
+  scoped_ptr<FakePictureLayerImpl> active_layer =
+      FakePictureLayerImpl::Create(active_tree, 10);
+  scoped_ptr<FakePictureLayerImpl> pending_layer =
+      FakePictureLayerImpl::Create(pending_tree, 10);
+
+  std::vector<PictureLayerImpl::Pair> layer_pairs;
+  host_impl_->GetPictureLayerImplPairs(&layer_pairs);
+
+  EXPECT_EQ(2u, layer_pairs.size());
+  if (layer_pairs[0].active) {
+    EXPECT_EQ(active_layer.get(), layer_pairs[0].active);
+    EXPECT_EQ(NULL, layer_pairs[0].pending);
+  } else {
+    EXPECT_EQ(pending_layer.get(), layer_pairs[0].pending);
+    EXPECT_EQ(NULL, layer_pairs[0].active);
+  }
+
+  if (layer_pairs[1].active) {
+    EXPECT_EQ(active_layer.get(), layer_pairs[1].active);
+    EXPECT_EQ(NULL, layer_pairs[1].pending);
+  } else {
+    EXPECT_EQ(pending_layer.get(), layer_pairs[1].pending);
+    EXPECT_EQ(NULL, layer_pairs[1].active);
+  }
+
+  active_layer->set_twin_layer(pending_layer.get());
+  pending_layer->set_twin_layer(active_layer.get());
+
+  host_impl_->GetPictureLayerImplPairs(&layer_pairs);
+  EXPECT_EQ(1u, layer_pairs.size());
+
+  EXPECT_EQ(active_layer.get(), layer_pairs[0].active);
+  EXPECT_EQ(pending_layer.get(), layer_pairs[0].pending);
+}
+
 }  // namespace
 }  // namespace cc