cc : Push layer lists instead of layer tree at commit and activation

cc/trees/layer_tree_host_unittest_scroll.cc

Index: cc/trees/layer_tree_host_unittest_scroll.cc
diff --git a/cc/trees/layer_tree_host_unittest_scroll.cc b/cc/trees/layer_tree_host_unittest_scroll.cc
index 6e685a5959b0bc68d3f404ada0608d9fa285971c..bae56af8d9c3c735cbc78df38c2d750c52442c61 100644
--- a/cc/trees/layer_tree_host_unittest_scroll.cc
+++ b/cc/trees/layer_tree_host_unittest_scroll.cc
@@ -1147,55 +1147,60 @@ class LayerTreeHostScrollTestScrollZeroMaxScrollOffset
     PostSetNeedsCommitToMainThread();
   }
 
+  void WillCommit() override {

[ajuma, 2016/06/09 15:15:19]

If this is changed to UpdateLayerTreeHost, it will get called before the usual
call to building property trees, and then you won't need the
BuildPropertyTreesForTesting calls below.

[jaydasika, 2016/06/09 16:56:25]

Done.

+    Layer* root = layer_tree_host()->root_layer();
+    Layer* scroll_layer = layer_tree_host()->outer_viewport_scroll_layer();
+    switch (layer_tree_host()->source_frame_number()) {
+      case 0:
+        scroll_layer->SetScrollClipLayerId(outer_viewport_container_layer_id_);
+        // Set max_scroll_offset = (100, 100).
+        scroll_layer->SetBounds(gfx::Size(root->bounds().width() + 100,
+                                          root->bounds().height() + 100));
+        root->layer_tree_host()->BuildPropertyTreesForTesting();
+        break;
+      case 1:
+        // Set max_scroll_offset = (0, 0).
+        scroll_layer->SetBounds(root->bounds());
+        root->layer_tree_host()->BuildPropertyTreesForTesting();
+        break;
+      case 2:
+        // Set max_scroll_offset = (-100, -100).
+        scroll_layer->SetBounds(gfx::Size());
+        root->layer_tree_host()->BuildPropertyTreesForTesting();
+        break;
+    }
+  }
+
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
     LayerImpl* scroll_layer = impl->OuterViewportScrollLayer();
-    scroll_layer->SetScrollClipLayer(outer_viewport_container_layer_id_);
-
-    // Set max_scroll_offset = (100, 100).
-    scroll_layer->SetBounds(
-        gfx::Size(root->bounds().width() + 100, root->bounds().height() + 100));
-    impl->active_tree()->property_trees()->needs_rebuild = true;
-    impl->active_tree()->BuildLayerListAndPropertyTreesForTesting();
 
     ScrollTree& scroll_tree =
         impl->active_tree()->property_trees()->scroll_tree;
     ScrollNode* scroll_node =
         scroll_tree.Node(scroll_layer->scroll_tree_index());
-
     InputHandler::ScrollStatus status =
         impl->TryScroll(gfx::PointF(0.0f, 1.0f), InputHandler::TOUCHSCREEN,
                         scroll_tree, scroll_node);
-
-    EXPECT_EQ(InputHandler::SCROLL_ON_IMPL_THREAD, status.thread);
-    EXPECT_EQ(MainThreadScrollingReason::kNotScrollingOnMain,
-              status.main_thread_scrolling_reasons);
-
-    // Set max_scroll_offset = (0, 0).
-    scroll_layer->SetBounds(root->bounds());
-    impl->active_tree()->property_trees()->needs_rebuild = true;
-    impl->active_tree()->BuildLayerListAndPropertyTreesForTesting();
-    scroll_tree = impl->active_tree()->property_trees()->scroll_tree;
-    scroll_node = scroll_tree.Node(scroll_layer->scroll_tree_index());
-    status = impl->TryScroll(gfx::PointF(0.0f, 1.0f), InputHandler::TOUCHSCREEN,
-                             scroll_tree, scroll_node);
-    EXPECT_EQ(InputHandler::SCROLL_IGNORED, status.thread);
-    EXPECT_EQ(MainThreadScrollingReason::kNotScrollable,
-              status.main_thread_scrolling_reasons);
-
-    // Set max_scroll_offset = (-100, -100).
-    scroll_layer->SetBounds(gfx::Size());
-    impl->active_tree()->property_trees()->needs_rebuild = true;
-    impl->active_tree()->BuildLayerListAndPropertyTreesForTesting();
-    scroll_tree = impl->active_tree()->property_trees()->scroll_tree;
-    scroll_node = scroll_tree.Node(scroll_layer->scroll_tree_index());
-    status = impl->TryScroll(gfx::PointF(0.0f, 1.0f), InputHandler::TOUCHSCREEN,
-                             scroll_tree, scroll_node);
-    EXPECT_EQ(InputHandler::SCROLL_IGNORED, status.thread);
-    EXPECT_EQ(MainThreadScrollingReason::kNotScrollable,
-              status.main_thread_scrolling_reasons);
-
-    EndTest();
+    switch (impl->active_tree()->source_frame_number()) {
+      case 0:
+        EXPECT_EQ(InputHandler::SCROLL_ON_IMPL_THREAD, status.thread);
+        EXPECT_EQ(MainThreadScrollingReason::kNotScrollingOnMain,
+                  status.main_thread_scrolling_reasons);
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 1:
+        EXPECT_EQ(InputHandler::SCROLL_IGNORED, status.thread);
+        EXPECT_EQ(MainThreadScrollingReason::kNotScrollable,
+                  status.main_thread_scrolling_reasons);
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 2:
+        EXPECT_EQ(InputHandler::SCROLL_IGNORED, status.thread);
+        EXPECT_EQ(MainThreadScrollingReason::kNotScrollable,
+                  status.main_thread_scrolling_reasons);
+        EndTest();
+        break;
+    }
   }
 
   void AfterTest() override {}