Implement hit tests/client area.

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 9fbd03f3146a5073be224f61347b7fda5e2a2c63..61ecab8c04674937bc991f0b2737e3243a462570 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -1503,6 +1503,23 @@ void WindowTreeClient::OnWindowTreeHostBoundsWillChange(
                                window_tree_host->GetBounds(), bounds);
 }
 
+void WindowTreeClient::OnWindowTreeHostClientAreaWillChange(
+    WindowTreeHostMus* window_tree_host,
+    const gfx::Insets& insets) {
+  SetClientArea(window_tree_host->window(), insets, std::vector<gfx::Rect>());

[sky, 2016/11/19 15:29:31]

optional: I don't think anyone else is calling SetClientArea/ClearHitTestMask
and SetHitTestMask. How about moving the implementations to these functions?

[Elliot Glaysher, 2016/11/22 00:48:07]

Done.

+}
+
+void WindowTreeClient::OnWindowTreeHostClearHitTestMask(
+    WindowTreeHostMus* window_tree_host) {
+  ClearHitTestMask(window_tree_host->window());
+}
+
+void WindowTreeClient::OnWindowTreeHostHitTestMaskWillChange(
+    WindowTreeHostMus* window_tree_host,
+    const gfx::Rect& mask_rect) {
+  SetHitTestMask(window_tree_host->window(), mask_rect);
+}
+
 std::unique_ptr<WindowPortMus> WindowTreeClient::CreateWindowPortForTopLevel() {
   std::unique_ptr<WindowPortMus> window_port =
       base::MakeUnique<WindowPortMus>(this, WindowMusType::TOP_LEVEL);