Remove FrameGenerator::root_window_

services/ui/ws/platform_display_default.cc

Index: services/ui/ws/platform_display_default.cc
diff --git a/services/ui/ws/platform_display_default.cc b/services/ui/ws/platform_display_default.cc
index a126d699c0df820a8eb3ad71a2dd2ebf75ed8794..c69e5d387acd4949be253c59a13b0aed0809f693 100644
--- a/services/ui/ws/platform_display_default.cc
+++ b/services/ui/ws/platform_display_default.cc
@@ -37,11 +37,12 @@ PlatformDisplayDefault::PlatformDisplayDefault(
       image_cursors_(new ImageCursors),
 #endif
       metrics_(metrics),
-      widget_(gfx::kNullAcceleratedWidget),
-      init_device_scale_factor_(metrics.device_scale_factor) {
+      widget_(gfx::kNullAcceleratedWidget) {
+  root_window_->AddObserver(this);
 }
 
 PlatformDisplayDefault::~PlatformDisplayDefault() {
+  root_window_->RemoveObserver(this);
   // Don't notify the delegate from the destructor.
   delegate_ = nullptr;
 
@@ -257,8 +258,10 @@ void PlatformDisplayDefault::OnAcceleratedWidgetAvailable(
           std::move(display_private),
           std::move(compositor_frame_sink_client_request));
   frame_generator_ = base::MakeUnique<FrameGenerator>(
-      root_window_, std::move(display_client_compositor_frame_sink));
-  frame_generator_->SetDeviceScaleFactor(init_device_scale_factor_);
+      std::move(display_client_compositor_frame_sink));
+  frame_generator_->OnWindowVisibilityChanged(root_window_->visible());
+  frame_generator_->OnWindowBoundsChanged(root_window_->bounds());
+  frame_generator_->SetDeviceScaleFactor(metrics_.device_scale_factor);
 }
 
 void PlatformDisplayDefault::OnAcceleratedWidgetDestroyed() {
@@ -267,5 +270,18 @@ void PlatformDisplayDefault::OnAcceleratedWidgetDestroyed() {
 
 void PlatformDisplayDefault::OnActivationChanged(bool active) {}
 
+void PlatformDisplayDefault::OnWindowBoundsChanged(

[msw, 2017/03/22 19:36:52]

Why not make FrameGenerator observe the ServerWindow directly?
(it seems odd to make PlatformDisplayDefault forward these calls)

[Alex Z., 2017/03/22 20:51:10]

We wanted to make FrameGenerator as simple as possible.

After some offline discussion, we decided to update bounds in 
PlatformDisplayDefault::UpdateViewportMetrics() and remove 
FrameGenerator::is_window_visible_.

+    ServerWindow* window,
+    const gfx::Rect& old_bounds,
+    const gfx::Rect& new_bounds) {
+  if (frame_generator_)
+    frame_generator_->OnWindowBoundsChanged(new_bounds);
+}
+
+void PlatformDisplayDefault::OnWindowVisibilityChanged(ServerWindow* window) {
+  if (frame_generator_)
+    frame_generator_->OnWindowVisibilityChanged(window->visible());
+}
+
 }  // namespace ws
 }  // namespace ui