Let RootWindowLayoutManager manages containers explicitly.

Bug: 969829
Test: no functional change. all test should passes.
Change-Id: I51ae9d1fc03b15f20a004d63c4e4c214d18d2652
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1656054
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#668515}

ash/root_window_controller.cc

@@ -269,22 +269,6 @@ void ReparentAllWindows(aura::Window* src, aura::Window* dst) {
   }
 }
 
-// Creates a new window for use as a container.
-aura::Window* CreateContainer(int window_id,
-                              const char* name,
-                              aura::Window* parent) {
-  aura::Window* window =
-      window_factory::NewWindow(nullptr, aura::client::WINDOW_TYPE_UNKNOWN)
-          .release();
-  window->Init(ui::LAYER_NOT_DRAWN);
-  window->set_id(window_id);
-  window->SetName(name);
-  parent->AddChild(window);
-  if (window_id != kShellWindowId_UnparentedControlContainer)
-    window->Show();
-  return window;
-}
-
 bool ShouldDestroyWindowInCloseChildWindows(aura::Window* window) {
   return window->owned_by_parent();
 }
@@ -651,6 +635,8 @@ void RootWindowController::CloseChildWindows() {
       delete toplevel_windows.Pop();
   }
 
+  // Reset layout manager so that it won't fire unnecessary layout evetns.
+  root->SetLayoutManager(nullptr);
   // And then remove the containers.
   while (!root->children().empty()) {
     aura::Window* child = root->children()[0];
@@ -844,7 +830,6 @@ void RootWindowController::InitLayoutManagers() {
   aura::Window* root = GetRootWindow();
   shelf_->CreateShelfWidget(root);
 
-  root_window_layout_manager_ = new wm::RootWindowLayoutManager(root);
   root->SetLayoutManager(root_window_layout_manager_);
 
   for (auto* container : desks_util::GetDesksContainers(root)) {
@@ -901,6 +886,8 @@ void RootWindowController::InitLayoutManagers() {
 
 void RootWindowController::CreateContainers() {
   aura::Window* root = GetRootWindow();
+  root_window_layout_manager_ = new wm::RootWindowLayoutManager(root);
+
   // For screen rotation animation: add a NOT_DRAWN layer in between the
   // root_window's layer and its current children so that we only need to
   // initiate two LayerAnimationSequences. One for the new layers and one for
@@ -1141,6 +1128,22 @@ void RootWindowController::CreateContainers() {
                   "PowerButtonAnimationContainer", magnified_container);
 }
 
+aura::Window* RootWindowController::CreateContainer(int window_id,
+                                                    const char* name,
+                                                    aura::Window* parent) {
+  aura::Window* window =
+      window_factory::NewWindow(nullptr, aura::client::WINDOW_TYPE_UNKNOWN)
+          .release();
+  window->Init(ui::LAYER_NOT_DRAWN);
+  window->set_id(window_id);
+  window->SetName(name);
+  parent->AddChild(window);
+  if (window_id != kShellWindowId_UnparentedControlContainer)
+    window->Show();
+  root_window_layout_manager_->AddContainer(window);
+  return window;
+}
+
 void RootWindowController::CreateSystemWallpaper(
     RootWindowType root_window_type) {
   SkColor color = SK_ColorBLACK;

ash/root_window_controller.h

@@ -248,6 +248,11 @@ class ASH_EXPORT RootWindowController {
   // Creates the containers (aura::Windows) used by the shell.
   void CreateContainers();
 
+  // Creates a new window for use as a container.
+  aura::Window* CreateContainer(int window_id,
+                                const char* name,
+                                aura::Window* parent);
+
   // Initializes |system_wallpaper_| and possibly also |boot_splash_screen_|.
   // The initial color is determined by the |root_window_type| and whether or
   // not this is the first boot.

ash/wm/root_window_layout_manager.cc

@@ -9,33 +9,6 @@
 
 namespace ash {
 
-namespace {
-
-// Resize all container windows that RootWindowLayoutManager is responsible for.
-// That includes all container windows up to depth four except the top level
-// windows which have a delegate. We cannot simply check top level windows,
-// because we need to skip other windows without a delegate, such as
-// ScreenDimmer windows.
-// TODO(wutao): The above logic is error prone. Consider using a Shell window id
-// to indentify such a container.
-void ResizeWindow(const aura::Window::Windows& children,
-                  const gfx::Rect& fullscreen_bounds,
-                  int depth) {
-  if (depth > 3)
-    return;
-  const int child_depth = depth + 1;
-  aura::WindowTracker children_tracker(children);
-  while (!children_tracker.windows().empty()) {
-    aura::Window* child = children_tracker.Pop();
-    if (child->GetToplevelWindow())
-      continue;
-    child->SetBounds(fullscreen_bounds);
-    ResizeWindow(child->children(), fullscreen_bounds, child_depth);
-  }
-}
-
-}  // namespace
-
 namespace wm {
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -50,7 +23,9 @@ RootWindowLayoutManager::~RootWindowLayoutManager() = default;
 // RootWindowLayoutManager, aura::LayoutManager implementation:
 
 void RootWindowLayoutManager::OnWindowResized() {
-  ResizeWindow(owner_->children(), gfx::Rect(owner_->bounds().size()), 0);
+  gfx::Rect bounds(owner_->bounds().size());
+  for (auto* container : containers_)
+    container->SetBounds(bounds);
 }
 
 void RootWindowLayoutManager::OnWindowAddedToLayout(aura::Window* child) {}
@@ -70,5 +45,10 @@ void RootWindowLayoutManager::SetChildBounds(
   SetChildBoundsDirect(child, requested_bounds);
 }
 
+void RootWindowLayoutManager::AddContainer(aura::Window* window) {
+  DCHECK(!window->GetToplevelWindow());
+  containers_.push_back(window);
+}
+
 }  // namespace wm
 }  // namespace ash

ash/wm/root_window_layout_manager.h

@@ -5,6 +5,8 @@
 #ifndef ASH_WM_ROOT_WINDOW_LAYOUT_MANAGER_H_
 #define ASH_WM_ROOT_WINDOW_LAYOUT_MANAGER_H_
 
+#include <vector>
+
 #include "base/macros.h"
 #include "ui/aura/layout_manager.h"
 
@@ -29,8 +31,11 @@ class RootWindowLayoutManager : public aura::LayoutManager {
   void SetChildBounds(aura::Window* child,
                       const gfx::Rect& requested_bounds) override;
 
+  void AddContainer(aura::Window* window);
+
  private:
   aura::Window* owner_;
+  std::vector<aura::Window*> containers_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindowLayoutManager);
 };