Close mirroring window only when necessary

always recreating was causing extra XRANR event on X11 system.

Delete WindowTreeHost asynchronously when the change can be made via input event.

BUG=484580,486190
TEST=tested manually. no flicker.

Review URL: https://codereview.chromium.org/1133323002

Cr-Commit-Position: refs/heads/master@{#329761}

ash/display/display_controller.cc

@@ -805,8 +805,8 @@ void DisplayController::CreateOrUpdateMirroringDisplay(
   }
 }
 
-void DisplayController::CloseMirroringDisplay() {
-  mirror_window_controller_->Close();
+void DisplayController::CloseMirroringDisplayIfNotNecessary() {
+  mirror_window_controller_->CloseIfNotNecessary();
   // If cursor_compositing is enabled for large cursor, the cursor window is
   // always on the desktop display (the visible cursor on the non-desktop
   // display is drawn through compositor mirroring). Therefore, it's unnecessary

ash/display/display_controller.h

@@ -159,7 +159,7 @@ class ASH_EXPORT DisplayController : public gfx::DisplayObserver,
   // aura::DisplayManager::Delegate overrides:
   void CreateOrUpdateMirroringDisplay(
       const DisplayInfoList& info_list) override;
-  void CloseMirroringDisplay() override;
+  void CloseMirroringDisplayIfNotNecessary() override;
   void PreDisplayConfigurationChange(bool clear_focus) override;
   void PostDisplayConfigurationChange() override;
 

ash/display/display_manager.cc

@@ -673,12 +673,13 @@ void DisplayManager::UpdateDisplays(
   std::sort(new_display_info_list.begin(),
             new_display_info_list.end(),
             DisplayInfoSortFunctor());
+
+  CreateSoftwareMirroringDisplayInfo(&new_display_info_list);
+
   // Close the mirroring window if any here to avoid creating two compositor on
   // one display.
   if (delegate_)
-    delegate_->CloseMirroringDisplay();
-
-  CreateSoftwareMirroringDisplay(&new_display_info_list);
+    delegate_->CloseMirroringDisplayIfNotNecessary();
 
   DisplayList new_displays;
   DisplayList removed_displays;
@@ -1081,7 +1082,7 @@ void DisplayManager::UpdateInternalDisplayModeListForTest() {
   SetInternalDisplayModeList(info);
 }
 
-void DisplayManager::CreateSoftwareMirroringDisplay(
+void DisplayManager::CreateSoftwareMirroringDisplayInfo(
     DisplayInfoList* display_info_list) {
   // Use the internal display or 1st as the mirror source, then scale
   // the root window so that it matches the external display's

ash/display/display_manager.h

@@ -65,8 +65,8 @@ class ASH_EXPORT DisplayManager
     virtual void CreateOrUpdateMirroringDisplay(
         const DisplayInfoList& display_info_list) = 0;
 
-    // Closes the mirror window if exists.
-    virtual void CloseMirroringDisplay() = 0;
+    // Closes the mirror window if not necessary.
+    virtual void CloseMirroringDisplayIfNotNecessary() = 0;
 
     // Called before and after the display configuration changes.
     // When |clear_focus| is true, the implementation should
@@ -343,7 +343,7 @@ private:
 
   // Creates software mirroring display related information. The display
   // used to mirror the content is removed from the |display_info_list|.
-  void CreateSoftwareMirroringDisplay(DisplayInfoList* display_info_list);
+  void CreateSoftwareMirroringDisplayInfo(DisplayInfoList* display_info_list);
 
   gfx::Display* FindDisplayForId(int64 id);
 

ash/display/mirror_window_controller.cc

@@ -136,12 +136,13 @@ MirrorWindowController::MirroringHostInfo::~MirroringHostInfo() {
 }
 
 MirrorWindowController::MirrorWindowController()
-    : screen_position_client_(new MirroringScreenPositionClient(this)) {
+    : multi_display_mode_(DisplayManager::EXTENDED),
+      screen_position_client_(new MirroringScreenPositionClient(this)) {
 }
 
 MirrorWindowController::~MirrorWindowController() {
   // Make sure the root window gets deleted before cursor_window_delegate.
-  Close();
+  Close(false);
 }
 
 void MirrorWindowController::UpdateWindow(
@@ -247,7 +248,7 @@ void MirrorWindowController::UpdateWindow(
                        [iter](const DisplayInfo& info) {
                          return info.id() == iter->first;
                        }) == display_info_list.end()) {
-        CloseAndDeleteHost(iter->second);
+        CloseAndDeleteHost(iter->second, true);
         iter = mirroring_host_info_map_.erase(iter);
       } else {
         ++iter;
@@ -266,10 +267,23 @@ void MirrorWindowController::UpdateWindow() {
   UpdateWindow(display_info_list);
 }
 
-void MirrorWindowController::Close() {
-  for (auto& info : mirroring_host_info_map_) {
-    CloseAndDeleteHost(info.second);
-  }
+void MirrorWindowController::CloseIfNotNecessary() {
+  DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+
+  DisplayManager::MultiDisplayMode new_mode =
+      display_manager->IsInUnifiedMode()
+          ? DisplayManager::UNIFIED
+          : (display_manager->IsInMirrorMode() ? DisplayManager::MIRRORING
+                                               : DisplayManager::EXTENDED);
+  if (multi_display_mode_ != new_mode)
+    Close(true);
+  multi_display_mode_ = new_mode;
+}
+
+void MirrorWindowController::Close(bool delay_host_deletion) {
+  for (auto& info : mirroring_host_info_map_)
+    CloseAndDeleteHost(info.second, delay_host_deletion);
+
   mirroring_host_info_map_.clear();
   if (reflector_) {
     aura::Env::GetInstance()->context_factory()->RemoveReflector(
@@ -342,7 +356,8 @@ aura::Window::Windows MirrorWindowController::GetAllRootWindows() const {
   return root_windows;
 }
 
-void MirrorWindowController::CloseAndDeleteHost(MirroringHostInfo* host_info) {
+void MirrorWindowController::CloseAndDeleteHost(MirroringHostInfo* host_info,
+                                                bool delay_host_deletion) {
   aura::WindowTreeHost* host = host_info->ash_host->AsWindowTreeHost();
 
   aura::client::SetScreenPositionClient(host->window(), nullptr);
@@ -357,6 +372,12 @@ void MirrorWindowController::CloseAndDeleteHost(MirroringHostInfo* host_info) {
   host_info->ash_host->PrepareForShutdown();
   reflector_->RemoveMirroringLayer(host_info->mirror_window->layer());
 
+  // EventProcessor may be accessed after this call if the mirroring window
+  // was deleted as a result of input event (e.g. shortcut), so don't delete
+  // now.
+  if (delay_host_deletion)
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, host_info);
+  else
     delete host_info;
 }
 

ash/display/mirror_window_controller.h

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/display/display_manager.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ -57,8 +58,8 @@ class ASH_EXPORT MirrorWindowController : public aura::WindowTreeHostObserver {
   // for the mirrored display.
   void UpdateWindow();
 
-  // Close the mirror window.
-  void Close();
+  // Close the mirror window if they're not necessary any longer.
+  void CloseIfNotNecessary();
 
   // aura::WindowTreeHostObserver overrides:
   void OnHostResized(const aura::WindowTreeHost* host) override;
@@ -81,7 +82,13 @@ class ASH_EXPORT MirrorWindowController : public aura::WindowTreeHostObserver {
 
   struct MirroringHostInfo;
 
-  void CloseAndDeleteHost(MirroringHostInfo* host_info);
+  // Close the mirror window. When |delay_host_deletion| is true, the window
+  // tree host will be deleted in an another task on UI thread. This is
+  // necessary to safely delete the WTH that is currently handling input events.
+  void Close(bool delay_host_deletion);
+
+  void CloseAndDeleteHost(MirroringHostInfo* host_info,
+                          bool delay_host_deletion);
 
   // Creates a RootWindowTransformer for current display
   // configuration.
@@ -90,6 +97,8 @@ class ASH_EXPORT MirrorWindowController : public aura::WindowTreeHostObserver {
   typedef std::map<int64_t, MirroringHostInfo*> MirroringHostInfoMap;
   MirroringHostInfoMap mirroring_host_info_map_;
 
+  DisplayManager::MultiDisplayMode multi_display_mode_;
+
   scoped_ptr<aura::client::ScreenPositionClient> screen_position_client_;
 
   scoped_ptr<ui::Reflector> reflector_;

ash/shell.cc

@@ -758,7 +758,6 @@ Shell::~Shell() {
 
   // Destroy all child windows including widgets.
   display_controller_->CloseChildWindows();
-  display_controller_->CloseMirroringDisplay();
 
   // Chrome implementation of shelf delegate depends on FocusClient,
   // so must be deleted before |focus_client_|.