aura: Add X11 host window management.

ui/aura/hostwm/host_window_manager_x11.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/aura/hostwm/host_window_manager_x11.h"
+
+#include <X11/Xutil.h>
+#include <X11/cursorfont.h>
+#include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xdamage.h>
+
+#include "base/bind.h"
+#include "base/message_pump_aurax11.h"
+#include "ui/aura/client/window_types.h"
+#include "ui/aura/dispatcher_linux.h"
+#include "ui/aura/env.h"
+#include "ui/aura/event.h"
+#include "ui/aura/focus_manager.h"
+#include "ui/aura/hostwm/host_window_manager_client.h"
+#include "ui/aura/root_window.h"
+#include "ui/aura/root_window_host_linux.h"
+#include "ui/aura/window.h"
+#include "ui/base/touch/touch_factory.h"
+#include "ui/base/x/x11_util.h"
+
+namespace {
+
+class ScopedPtrXFree {
+ public:
+  void operator()(void* x) const {
+    ::XFree(x);
+  }
+};
+
+int ExistingWMX11ErrorHandler(Display* d, XErrorEvent* e) {
+  LOG(FATAL)
+    << "X Error detected: "
+    << "serial " << e->serial << ", "
+    << "error_code " << static_cast<int>(e->error_code) << ", "
+    << "request_code " << static_cast<int>(e->request_code) << ", "
+    << "minor_code " << static_cast<int>(e->minor_code);
+  return 0;
+}
+
+std::queue<unsigned long> xerror_ignore_queue;
+
+int FilteredX11ErrorHandler(Display* d, XErrorEvent* e) {
+  while (!xerror_ignore_queue.empty()) {
+    if ((e->serial - xerror_ignore_queue.front()) > 0) {
+      xerror_ignore_queue.pop();
+      continue;
+    }
+
+    break;
+  }
+
+  if (!xerror_ignore_queue.empty() && xerror_ignore_queue.front() == e->serial)
+    return 0;
+
+  return aura::CallBaseX11ErrorHandler(d, e);
+}
+
+unsigned InitWindowChanges(const gfx::Rect& bounds,
+                           ::Window siblingToStackAbove,
+                           XWindowChanges& wc) {
+  wc.x = bounds.x();
+  wc.y = bounds.y();
+  wc.width = bounds.width();
+  wc.height = bounds.height();
+  if (!siblingToStackAbove) {
+    wc.stack_mode = Below;
+    return CWX | CWY | CWWidth | CWHeight | CWStackMode;
+  }
+
+  wc.sibling = siblingToStackAbove;
+  wc.stack_mode = Above;
+  return CWX | CWY | CWWidth | CWHeight | CWStackMode | CWSibling;
+}
+
+aura::Window* FindLowestCommonAncestor(
+    aura::Window* root, aura::Window* p, aura::Window* q) {
+  // Root is the LCA.
+  if (root == p || root == q)
+    return root;
+
+  aura::Window* prev = NULL;
+  const aura::Window::Windows& children = root->children();
+  for (size_t i = 0; i < children.size(); ++i) {
+
+    // Try to find LCA of p and q in subtree.
+    aura::Window* next = FindLowestCommonAncestor(children[i], p, q);
+    if (next) {
+
+      // If a LCA was previously found, p and q must be in different subtrees.
+      if (prev)
+        return root;
+
+      prev = next;
+    }
+  }
+
+  return prev;
+}
+
+gfx::Point GetTargetOriginInRootWindow(aura::Window* window) {
+  gfx::Point origin;
+
+  const aura::Window* p = window;
+  for (; p != window->GetRootWindow(); p = p->parent())
+    origin = origin.Add(p->GetTargetBounds().origin());
+
+  return origin;
+}
+
+gfx::Rect GetTargetBoundsInRootWindow(aura::Window* window) {
+  return gfx::Rect(
+      GetTargetOriginInRootWindow(window),
+      window->GetTargetBounds().size());
+}
+
+const char* kAtomsToCache[] = {
+  "WM_DELETE_WINDOW",
+  "WM_PROTOCOLS",
+  NULL
+};
+
+}
+
+namespace aura {
+
+XErrorHandler base_xerror_handler_ = 0;
+
+void SetBaseX11ErrorHandler(XErrorHandler error_handler) {
+  DCHECK(!base_xerror_handler_);
+  base_xerror_handler_ = error_handler;
+}
+
+int CallBaseX11ErrorHandler(Display* d, XErrorEvent* e) {
+  DCHECK(base_xerror_handler_);
+  return base_xerror_handler_(d, e);
+}
+
+HostWindowManagerX11WindowObserver::HostWindowManagerX11WindowObserver(
+    HostWindowManagerX11* manager)
+    : host_window_manager_(manager) {
+}
+
+void HostWindowManagerX11WindowObserver::OnWindowInitialized(Window* window) {
+  window->AddObserver(this);
+}
+
+void HostWindowManagerX11WindowObserver::OnWillRemoveWindow(Window* window) {
+  HostWindowManagerX11* wm = host_window_manager_;
+
+  if (wm->configure_window_ == window)
+    wm->configure_window_ = window->parent();
+}
+
+void HostWindowManagerX11WindowObserver::OnWindowDestroyed(Window* window) {
+  HostWindowManagerX11* wm = host_window_manager_;
+
+  if (wm->input_host_windows_.find(window) != wm->input_host_windows_.end()) {
+    scoped_refptr<HostWindowX11> top_level = wm->input_host_windows_[window];
+    wm->native_windows_.erase(top_level->xid());
+    wm->input_host_windows_.erase(window);
+    top_level->CloseWindow();
+  }
+
+  // This should only happend at close down.
+  if (wm->host_windows_.find(window) != wm->host_windows_.end()) {
+    wm->native_windows_.erase(wm->host_windows_[window]);
+    wm->host_windows_.erase(window);
+  }
+}
+
+void HostWindowManagerX11WindowObserver::OnWindowStackingChanged(
+    Window* window) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  wm->HostWindowNeedsConfigure(window->parent());
+}
+
+void HostWindowManagerX11WindowObserver::OnWindowVisibilityChanged(
+    Window* window, bool visible) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  // Window can be parent-less when being destroyed.
+  if (window->parent())
+    wm->HostWindowNeedsConfigure(window);
+}
+
+void HostWindowManagerX11WindowObserver::OnWindowBoundsChanged(
+    Window* window, const gfx::Rect& old_bounds, const gfx::Rect& new_bounds) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  wm->HostWindowNeedsConfigure(window);
+}
+
+HostWindowX11::HostWindowX11(::XID xwindow, unsigned state)
+    : xdisplay_(base::MessagePumpAuraX11::GetDefaultXDisplay()),
+      xwindow_(xwindow),
+      state_(state) {
+}
+
+HostWindowX11::~HostWindowX11() {
+}
+
+bool HostWindowX11::CanResize() {
+  return false;
+}
+
+bool HostWindowX11::CanConfigure() {
+  return false;
+}
+
+bool HostWindowX11::CanActivate() {
+  return false;
+}
+
+InputHostWindowX11::InputHostWindowX11(::XID xwindow)
+    : HostWindowX11(xwindow, WithdrawnState) {
+}
+
+InputHostWindowX11::~InputHostWindowX11() {
+}
+
+void InputHostWindowX11::CloseWindow() {
+  XDestroyWindow(xdisplay_, xwindow_);
+}
+
+bool InputHostWindowX11::CanResize() {
+  return true;
+}
+
+bool InputHostWindowX11::CanConfigure() {
+  return true;
+}
+
+bool InputHostWindowX11::CanActivate() {
+  return false;
+}
+
+RedirectedHostWindowX11::RedirectedHostWindowX11(
+    HostWindowManagerX11* manager,
+    ::Window xwindow,
+    const gfx::Size& size)
+    : HostWindowX11(xwindow, WithdrawnState),
+      host_window_manager_(manager),
+      size_(size),
+      visible_(false) {
+  // Ignore possible X error as we can't guarantee that host window exists
+  // and is of InputOutput type.
+  xerror_ignore_queue.push(NextRequest(xdisplay_));
+  // Damage resource is automatically freed when the window is destroyed or
+  // we close our connection to the X server.
+  XDamageCreate(xdisplay_, xwindow_, XDamageReportRawRectangles);
+  static_cast<DispatcherLinux*>(
+      Env::GetInstance()->GetDispatcher())->
+      AddDispatcherForWindow(this, xwindow_);
+}
+
+RedirectedHostWindowX11::~RedirectedHostWindowX11() {
+  static_cast<DispatcherLinux*>(
+      Env::GetInstance()->GetDispatcher())->
+      RemoveDispatcherForWindow(xwindow_);
+}
+
+void RedirectedHostWindowX11::OnMapNotify() {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  if (wm->native_windows_.find(xwindow_) != wm->native_windows_.end())
+    client->OnHostWindowVisibilityChanged(wm->native_windows_[xwindow_], true);
+
+  SetVisible(true);
+}
+
+void RedirectedHostWindowX11::OnUnmapNotify() {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  if (wm->native_windows_.find(xwindow_) != wm->native_windows_.end())
+    client->OnHostWindowVisibilityChanged(
+        wm->native_windows_[xwindow_], false);
+
+  SetVisible(false);
+}
+
+void RedirectedHostWindowX11::OnConfigureNotify(
+    gfx::Rect bounds, ::Window above) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  if (wm->native_windows_.find(xwindow_) != wm->native_windows_.end())
+    client->OnHostWindowMovedOrResized(wm->native_windows_[xwindow_], bounds);
+
+  SetSize(bounds.size());
+
+  // TODO(reveman): Respect stacking properties.
+}
+
+bool RedirectedHostWindowX11::Dispatch(const base::NativeEvent& event) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  if (event->type == wm->damage_event_base() + XDamageNotify) {
+    UpdateExternalTexture();
+    return true;
+  }
+
+  switch (event->type) {
+  case ButtonPress: {
+    XEvent x_button_event = *event;
+    x_button_event.xbutton.x = event->xbutton.x_root;
+    x_button_event.xbutton.y = event->xbutton.y_root;
+    client->GetRootWindow()->DispatchNativeEvent(&x_button_event);
+    // We generate a ButtonRelease event here as we won't get a real release
+    // event when we replay event on the host window.
+    x_button_event.type = ButtonRelease;
+    client->GetRootWindow()->DispatchNativeEvent(&x_button_event);
+    XAllowEvents(xdisplay_, ReplayPointer, event->xbutton.time);
+    break;
+  }
+  case ButtonRelease:
+    NOTREACHED();
+    break;
+  case KeyPress:
+  case KeyRelease:
+    // TODO(reveman): Implement key grabs.
+    NOTREACHED();
+    break;
+  }
+  return true;
+}
+
+void RedirectedHostWindowX11::UpdateExternalTexture() {
+  // TODO(reveman): Get backing pixmap for window and bind to ui::Texture.
+}
+
+void RedirectedHostWindowX11::SetSize(const gfx::Size& size) {
+  if (size == size_)
+    return;
+
+  size_ = size;
+
+  // External texture will be updated as a result of receiving damage events.
+}
+
+void RedirectedHostWindowX11::SetVisible(bool visible) {
+  if (visible == visible_)
+    return;
+
+  visible_ = visible;
+}
+
+bool RedirectedHostWindowX11::CanResize() {
+  return false;
+}
+
+bool RedirectedHostWindowX11::CanConfigure() {
+  return false;
+}
+
+bool RedirectedHostWindowX11::CanActivate() {
+  return false;
+}
+
+ManagedRedirectedHostWindowX11::ManagedRedirectedHostWindowX11(
+    HostWindowManagerX11* manager, ::Window xwindow, const gfx::Size& size)
+    : RedirectedHostWindowX11(manager, xwindow, size) {
+}
+
+ManagedRedirectedHostWindowX11::~ManagedRedirectedHostWindowX11() {
+}
+
+void ManagedRedirectedHostWindowX11::CloseWindow() {
+  HostWindowManagerX11* wm = host_window_manager_;
+  XEvent xevent;
+  xevent.type = ClientMessage;
+  xevent.xclient.window = xwindow_;
+  xevent.xclient.message_type = wm->atom_cache_.GetAtom("WM_PROTOCOLS");
+  xevent.xclient.format = 32;
+  xevent.xclient.data.l[0] = wm->atom_cache_.GetAtom("WM_DELETE_WINDOW");
+  xevent.xclient.data.l[1] = CurrentTime;
+  xevent.xclient.data.l[2] = 0;
+  xevent.xclient.data.l[3] = 0;
+  xevent.xclient.data.l[4] = 0;
+  // Ignore possible X error as we can't guarantee that host window exists.
+  xerror_ignore_queue.push(NextRequest(xdisplay_));
+  XSendEvent(xdisplay_, xwindow_, false, NoEventMask, &xevent);
+}
+
+bool ManagedRedirectedHostWindowX11::CanResize() {
+  // TODO(reveman): Use hints to determine if host window can be resized.
+  return true;
+}
+
+void ManagedRedirectedHostWindowX11::OnMapNotify() {
+  SetVisible(true);
+}
+
+void ManagedRedirectedHostWindowX11::OnUnmapNotify() {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  // The client unmapped the window, we should transition to withdrawn state.
+  if (state_ == NormalState) {
+    if (wm->native_windows_.find(xwindow_) != wm->native_windows_.end())
+      client->OnHostWindowVisibilityChanged(
+          wm->native_windows_[xwindow_], false);
+
+    state_ = WithdrawnState;
+  }
+
+  SetVisible(false);
+}
+
+void ManagedRedirectedHostWindowX11::OnConfigureNotify(
+    gfx::Rect bounds, ::Window above) {
+  SetSize(bounds.size());
+}
+
+bool ManagedRedirectedHostWindowX11::CanConfigure() {
+  return true;
+}
+
+bool ManagedRedirectedHostWindowX11::CanActivate() {
+  return true;
+}
+
+HostWindowManagerX11RootEventObserver::HostWindowManagerX11RootEventObserver(
+    HostWindowManagerX11* manager)
+    : host_window_manager_(manager),
+      xdisplay_(base::MessagePumpAuraX11::GetDefaultXDisplay()) {
+}
+
+bool HostWindowManagerX11RootEventObserver::ProcessHostWindowUpdate(
+    const base::NativeEvent& event) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  ::Window xwindow = 0;
+  switch (event->type) {
+  case CreateNotify: {
+    int border_size = event->xcreatewindow.border_width * 2;
+    gfx::Rect bounds(event->xcreatewindow.x,
+                     event->xcreatewindow.y,
+                     event->xcreatewindow.width + border_size,
+                     event->xcreatewindow.height + border_size);
+    wm->RegisterNewTopLevel(event->xcreatewindow.window, bounds,
+                            !event->xcreatewindow.override_redirect);
+    xwindow = event->xcreatewindow.window;
+  } break;
+  case ReparentNotify:
+    if (event->xreparent.parent == wm->x_root_window_)
+      wm->RegisterNewTopLevel(event->xreparent.window);
+    xwindow = event->xreparent.window;
+    break;
+  case MapNotify:
+    xwindow = event->xmap.window;
+    break;
+  case UnmapNotify:
+    xwindow = event->xunmap.window;
+    break;
+  case DestroyNotify:
+    xwindow = event->xdestroywindow.window;
+    break;
+  case ConfigureNotify:
+    xwindow = event->xconfigure.window;
+    break;
+  default:
+    return false;
+  }
+
+  scoped_refptr<HostWindowX11> top_level = wm->top_level_windows_[xwindow];
+
+  DCHECK(top_level);
+
+  switch (event->type) {
+  case CreateNotify:
+    wm->HostWindowNeedsConfigure(client->GetRootWindow());
+    break;
+  case MapNotify:
+    top_level->OnMapNotify();
+    break;
+  case UnmapNotify:
+    top_level->OnUnmapNotify();
+    break;
+  case ReparentNotify:
+    if (event->xreparent.parent == wm->x_root_window_) {
+      wm->HostWindowNeedsConfigure(client->GetRootWindow());
+      break;
+    }
+
+    XUngrabButton(xdisplay_, AnyButton, AnyModifier, xwindow);
+
+    // TODO(danakj): grab keys on the window so we can use shortcuts
+    //XUngrabKey(xdisplay_, AnyKey, AnyModifier, xwindow);
+
+    // Fallthrough.
+  case DestroyNotify: {
+    if (wm->native_windows_.find(xwindow) != wm->native_windows_.end()) {
+      Window* window = wm->native_windows_[xwindow];
+
+      DCHECK(wm->input_host_windows_.find(window) ==
+             wm->input_host_windows_.end());
+
+      if (wm->host_windows_.find(window) != wm->host_windows_.end()) {
+        // Reset delegate before calling OnHostWindowDestroyed to make sure
+        // we're not preventing widget from being closed.
+        SetHostWindowDelegate(window, 0);
+        client->OnHostWindowDestroyed(window);
+        wm->host_windows_.erase(window);
+      }
+
+      wm->native_windows_.erase(xwindow);
+    }
+    wm->top_level_windows_.erase(xwindow);
+
+    // Window destruction could have caused a previous configure request to
+    // fail.
+    wm->HostWindowNeedsConfigure(client->GetRootWindow());
+  } break;
+  case ConfigureNotify: {
+    int bw = event->xconfigure.border_width * 2;
+    gfx::Rect bounds(event->xconfigure.x,
+                     event->xconfigure.y,
+                     event->xconfigure.width + bw,
+                     event->xconfigure.height + bw);
+    top_level->OnConfigureNotify(bounds, event->xconfigure.above);
+  } break;
+  }
+
+  return true;
+}
+
+bool HostWindowManagerX11RootEventObserver::ProcessHostWindowRequest(
+    const base::NativeEvent& event) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+
+  ::Window xwindow = 0;
+  switch (event->type) {
+  case MapRequest:
+    xwindow = event->xmaprequest.window;
+    break;
+  case ConfigureRequest:
+    xwindow = event->xconfigurerequest.window;
+    break;
+  case CirculateRequest:
+    xwindow = event->xcirculaterequest.window;
+    break;
+  default:
+    return false;
+  }
+
+  scoped_refptr<HostWindowX11> top_level = wm->top_level_windows_[xwindow];
+
+  DCHECK(top_level);
+  DCHECK(top_level->CanConfigure());
+
+  if (wm->native_windows_.find(xwindow) == wm->native_windows_.end())
+    return true;
+
+  Window* window = wm->native_windows_[xwindow];
+
+  switch (event->type) {
+  case MapRequest:
+    client->OnHostWindowMovedOrResizedConstrained(
+        window, GetTargetBoundsInRootWindow(window));
+    client->OnHostWindowVisibilityChanged(window, true);
+    break;
+  case ConfigureRequest: {
+    gfx::Rect bounds(GetTargetBoundsInRootWindow(window));
+    if (event->xconfigurerequest.value_mask & CWX)
+      bounds.set_x(event->xconfigurerequest.x);
+    if (event->xconfigurerequest.value_mask & CWY)
+      bounds.set_y(event->xconfigurerequest.y);
+    if (event->xconfigurerequest.value_mask & CWWidth)
+      bounds.set_width(event->xconfigurerequest.width);
+    if (event->xconfigurerequest.value_mask & CWHeight)
+      bounds.set_height(event->xconfigurerequest.height);
+    client->OnHostWindowMovedOrResizedConstrained(window, bounds);
+    // TODO(reveman): Respect stacking properties.
+  } break;
+  case CirculateRequest:
+    // TODO(reveman): Respect stacking properties.
+    break;
+  }
+
+  return true;
+}
+
+bool HostWindowManagerX11RootEventObserver::Dispatch(
+    const base::NativeEvent& event) {
+  if (ProcessHostWindowRequest(event))
+    return true;
+  if (ProcessHostWindowUpdate(event))
+    return true;
+
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+  // Let root window host handle all input events.
+  return client->GetRootWindow()->DispatchNativeEvent(event);
+}
+
+void HostWindowManagerX11RootEventObserver::OnWindowFocused(Window* window) {
+  HostWindowManagerX11* wm = host_window_manager_;
+  client::HostWindowManagerClient* client = wm->client_;
+  // We need to configure all windows when changing focus.
+  wm->HostWindowNeedsConfigure(client->GetRootWindow());
+}
+
+void HostWindowManagerX11RootEventObserver::OnCursorChanged(
+    const RootWindow* root, ui::PlatformCursor cursor) {
+  HostWindowManagerX11* wm = host_window_manager_;
+
+  // Set cursor for all input windows.
+  std::map<gfx::NativeWindow, scoped_refptr<InputHostWindowX11> >::iterator it;
+  for (it = wm->input_host_windows_.begin();
+       it != wm->input_host_windows_.end(); it++) {
+    scoped_refptr<HostWindowX11> input_window = (*it).second;
+    XDefineCursor(xdisplay_, input_window->xid(), cursor);
+  }
+}
+
+HostWindowManagerX11::HostWindowManagerX11(
+    client::HostWindowManagerClient* client)
+    : xdisplay_(base::MessagePumpAuraX11::GetDefaultXDisplay()),
+      x_root_window_(DefaultRootWindow(xdisplay_)),
+      configure_window_(0),
+      damage_event_base_(0),
+      window_observer_(new HostWindowManagerX11WindowObserver(this)),
+      event_observer_(new HostWindowManagerX11RootEventObserver(this)),
+      atom_cache_(xdisplay_, kAtomsToCache),
+      client_(client) {
+  // TODO(reveman): Check that damage extension is present.
+  int error_base_ignored;
+  XDamageQueryExtension(xdisplay_, &damage_event_base_, &error_base_ignored);
+}
+
+HostWindowManagerX11::~HostWindowManagerX11() {
+  XCompositeUnredirectSubwindows(xdisplay_, x_root_window_,
+                                 CompositeRedirectManual);
+
+  std::map< ::Window, gfx::NativeWindow>::iterator it;
+  for (it = native_windows_.begin(); it != native_windows_.end(); it++) {
+    if ((*it).second) {
+      Window* window = (*it).second;
+      SetHostWindowDelegate(window, 0);
+      client_->OnHostWindowDestroyed(window);
+      window->RemoveObserver(window_observer_.get());
+    }
+  }
+
+  top_level_windows_.clear();
+  native_windows_.clear();
+  host_windows_.clear();
+  input_host_windows_.clear();
+
+  Env::GetInstance()->RemoveObserver(window_observer_.get());
+  static_cast<DispatcherLinux*>(
+      Env::GetInstance()->GetDispatcher())->
+      RemoveDispatcherForRootWindow(event_observer_.get());
+  if (client_->GetRootWindow()) {
+    client_->GetRootWindow()->RemoveRootWindowObserver(event_observer_.get());
+    client_->GetRootWindow()->GetFocusManager()->RemoveObserver(
+        event_observer_.get());
+  }
+}
+
+::Window HostWindowManagerX11::GetTopHostWindow(Window* window) {
+  // children is ordered back to front, so walk through it in reverse.
+  const Window::Windows& children = window->children();
+  for (size_t i = children.size(); i; --i) {
+    ::Window top = GetTopHostWindow(children[i - 1]);
+    if (top)
+      return top;
+  }
+
+  if (host_windows_.find(window) != host_windows_.end()) {
+    ::Window host_window = host_windows_[window];
+    scoped_refptr<HostWindowX11> top_level = top_level_windows_[host_window];
+
+    DCHECK(top_level);
+    // Ignore windows that we're not allowed to configure.
+    if (top_level->CanConfigure())
+      return host_window;
+  }
+
+  if (input_host_windows_.find(window) != input_host_windows_.end())
+    return input_host_windows_[window]->xid();
+
+  return 0;
+}
+
+::Window HostWindowManagerX11::FindHostWindowToStackAbove(Window* window) {
+  Window* parent = window->parent();
+  if (!parent)
+    return 0;
+
+  ::Window above = 0;
+
+  const Window::Windows& children = parent->children();
+  for (size_t i = 0; i < children.size(); ++i) {
+    if (children[i] == window)
+      break;
+
+    ::Window top = GetTopHostWindow(children[i]);
+    if (top)
+      above = top;
+  }
+
+  if (!above)
+    above = FindHostWindowToStackAbove(parent);
+
+  return above;
+}
+
+void HostWindowManagerX11::CreateHostInputWindowIfNeeded(Window* window) {
+  // Ignore root window.
+  if (window == window->GetRootWindow())
+    return;
+
+  // Don't create host input window when there's already host window.
+  if (host_windows_.find(window) != host_windows_.end())
+    return;
+
+  // Avoid windows without delegates.
+  if (!window->delegate())
+    return;
+
+  // Delay creation until window is visible.
+  if (!window->IsVisible())
+    return;
+
+  // Host input window already exists.
+  if (input_host_windows_.find(window) != input_host_windows_.end())
+    return;
+
+  scoped_refptr<InputHostWindowX11> delegate = new InputHostWindowX11(
+      XCreateWindow(xdisplay_, x_root_window_, -100, -100, 1, 1,
+                    0, CopyFromParent, InputOnly, CopyFromParent, 0, 0));
+  SetHostWindowDelegate(window, delegate);
+  native_windows_[delegate->xid()] = window;
+  input_host_windows_[window] = delegate;
+}
+
+void HostWindowManagerX11::RecursiveConfigureHostWindow(
+    Window* window,
+    gfx::Point origin,
+    ::Window& sibling_to_stack_above,
+    ::Window& focus_window,
+    bool has_focus) {
+  RootWindow* root_window = window->GetRootWindow();
+
+  // Lazy creation of input only windows.
+  CreateHostInputWindowIfNeeded(window);
+
+  // Special case to ensure that root window is stacked properly.
+  if (window == root_window) {
+    XWindowChanges wc;
+    unsigned mask = InitWindowChanges(gfx::Rect(), sibling_to_stack_above, wc);
+    ::Window root_host_window =
+        root_window->GetAcceleratedWidgetUsedForEvents();
+    DCHECK(window->IsVisible());
+    XConfigureWindow(xdisplay_, root_host_window,
+                     mask & (CWSibling | CWStackMode),
+                     &wc);
+
+    sibling_to_stack_above = root_host_window;
+  }
+
+  // We never move focus to our internal input host windows.
+  if (input_host_windows_.find(window) != input_host_windows_.end()) {
+    scoped_refptr<HostWindowX11> input_window = input_host_windows_[window];
+    gfx::Rect host_bounds(origin, window->GetTargetBounds().size());
+    host_bounds.Inset(window->hit_test_bounds_override_outer());
+    gfx::Rect non_empty_bounds(
+        host_bounds.Union(gfx::Rect(host_bounds.origin(), gfx::Size(1, 1))));
+
+    if (!window->IsVisible()) {
+      if (input_window->state() == NormalState) {
+        XUnmapWindow(xdisplay_, input_window->xid());
+        input_window->set_state(IconicState);
+      }
+    }
+
+    XWindowChanges wc;
+    unsigned mask = InitWindowChanges(
+        non_empty_bounds, sibling_to_stack_above, wc);
+    // Ignore possible X error as we can't guarantee that host window exists.
+    if (mask & CWSibling)
+      xerror_ignore_queue.push(NextRequest(xdisplay_));
+    XConfigureWindow(xdisplay_, input_window->xid(), mask, &wc);
+
+    sibling_to_stack_above = input_window->xid();
+
+    if (window->IsVisible()) {
+      if (input_window->state() != NormalState) {
+        XMapWindow(xdisplay_, input_window->xid());
+        input_window->set_state(NormalState);
+      }
+    }
+  }
+
+  if (host_windows_.find(window) != host_windows_.end()) {
+    ::Window host_window = host_windows_[window];
+    scoped_refptr<HostWindowX11> top_level = top_level_windows_[host_window];
+
+    DCHECK(top_level);
+    if (top_level->CanConfigure()) {
+      gfx::Rect host_bounds(origin, window->GetTargetBounds().size());
+      gfx::Rect non_empty_bounds(
+          host_bounds.Union(gfx::Rect(host_bounds.origin(), gfx::Size(1, 1))));
+
+      if (!window->IsVisible()) {
+        if (top_level->state() == NormalState) {
+          // Ignore possible X error as we can't guarantee that host window
+          // exists.
+          xerror_ignore_queue.push(NextRequest(xdisplay_));
+          XUnmapWindow(xdisplay_, host_window);
+
+          top_level->set_state(IconicState);
+        }
+      }
+
+      XWindowChanges wc;
+      unsigned mask = InitWindowChanges(
+          non_empty_bounds, sibling_to_stack_above, wc);
+      // Get rid of any borders.
+      wc.border_width = 0;
+      mask |= CWBorderWidth;
+      // Ignore possible X error as we can't guarantee that host window exists.
+      xerror_ignore_queue.push(NextRequest(xdisplay_));
+      XConfigureWindow(xdisplay_, host_window, mask, &wc);
+
+      sibling_to_stack_above = host_window;
+
+      if (window->IsVisible()) {
+        if (top_level->state() != NormalState) {
+          // Ignore possible X error as we can't guarantee that host window
+          // exists.
+          xerror_ignore_queue.push(NextRequest(xdisplay_));
+          XMapWindow(xdisplay_, host_window);
+
+          // Grab buttons so that window can be activated when a click is
+          // received in the client area.
+          xerror_ignore_queue.push(NextRequest(xdisplay_));
+          XGrabButton(xdisplay_, AnyButton, AnyModifier, host_window, false,
+                      ButtonPressMask | ButtonReleaseMask | ButtonMotionMask,
+                      GrabModeSync, GrabModeAsync, 0, 0);
+
+          // TODO(danakj): grab keys on the window so we can use shortcuts
+          //XGrabKey(xdisplay_, AnyKey, AnyModifier, event->xmaprequest.window,
+          //         true, GrabModeAsync, GrabModeSync);
+
+          top_level->set_state(NormalState);
+        }
+
+        // Set |focus_window| to host window if aura sub-tree has focus.
+        if (has_focus)
+          focus_window = host_window;
+      }
+    }
+  }
+
+  const Window::Windows& children = window->children();
+  for (size_t i = 0; i < children.size(); ++i)
+    RecursiveConfigureHostWindow(
+        children[i],
+        origin.Add(children[i]->GetTargetBounds().origin()),
+        sibling_to_stack_above,
+        focus_window,
+        has_focus || window->HasFocus());
+}
+
+void HostWindowManagerX11::ConfigureHostWindows() {
+  if (!configure_window_)
+    return;
+
+  ::Window focus_window = 0;
+  ::Window sibling_to_stack_above =
+      FindHostWindowToStackAbove(configure_window_);
+  RecursiveConfigureHostWindow(
+      configure_window_,
+      GetTargetOriginInRootWindow(configure_window_),
+      sibling_to_stack_above,
+      focus_window,
+      configure_window_->HasFocus());
+
+  // Only set focus when we configure the root window.
+  if (configure_window_ == client_->GetRootWindow()) {
+    if (focus_window) {
+      // Ignore possible X error as we can't guarantee that host window exists.
+      xerror_ignore_queue.push(NextRequest(xdisplay_));
+      XSetInputFocus(xdisplay_, focus_window, 0, CurrentTime);
+    } else
+      XSetInputFocus(
+          xdisplay_,
+          client_->GetRootWindow()->GetAcceleratedWidgetUsedForEvents(),
+          0, CurrentTime);
+  }
+
+  configure_window_ = 0;
+}
+
+void HostWindowManagerX11::HostWindowNeedsConfigure(Window* window) {
+  DCHECK(window->GetRootWindow() == client_->GetRootWindow());
+  if (!configure_window_) {
+    configure_window_ = window;
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&HostWindowManagerX11::ConfigureHostWindows, AsWeakPtr()));
+  } else {
+    configure_window_ = FindLowestCommonAncestor(
+        window->GetRootWindow(), configure_window_, window);
+  }
+}
+
+void HostWindowManagerX11::Init() {
+  Env::GetInstance()->AddObserver(window_observer_.get());
+  static_cast<DispatcherLinux*>(
+      Env::GetInstance()->GetDispatcher())->
+      AddDispatcherForRootWindow(event_observer_.get());
+
+  // TODO(danakj): When env manages root windows, get it from there, and watch
+  // for monitor changes.
+  client_->GetRootWindow()->AddRootWindowObserver(event_observer_.get());
+  client_->GetRootWindow()->GetFocusManager()->AddObserver(
+      event_observer_.get());
+
+  if (client_->GetRootWindow()->GetAcceleratedWidget() ==
+      client_->GetRootWindow()->GetAcceleratedWidgetUsedForEvents())
+    LOG(FATAL) << "Overlay window must be used as output. Try using "
+      "--aura-host-window-use-fullscreen.";
+
+  int root_mask = ButtonPressMask | ButtonReleaseMask | PointerMotionMask |
+      EnterWindowMask | LeaveWindowMask | SubstructureRedirectMask |
+      SubstructureNotifyMask;
+
+  XGrabServer(xdisplay_);
+
+  ::Window root, parent, *children = 0;
+  unsigned int nchildren;
+  XQueryTree(xdisplay_, x_root_window_, &root, &parent, &children, &nchildren);
+  scoped_ptr_malloc< ::Window, ScopedPtrXFree> xwindows(children);
+
+  XErrorHandler error_handler = XSetErrorHandler(ExistingWMX11ErrorHandler);
+  XWindowAttributes attr;
+  XGetWindowAttributes(xdisplay_, x_root_window_, &attr);
+  XSelectInput(xdisplay_, x_root_window_, attr.your_event_mask | root_mask);
+  // Redirect top-level windows to offscreen buffers.
+  XCompositeRedirectSubwindows(xdisplay_, x_root_window_,
+                               CompositeRedirectManual);
+  XSync(xdisplay_, 0);
+  XSetErrorHandler(error_handler);
+
+  // Install filtered error handler.
+  SetBaseX11ErrorHandler(XSetErrorHandler(FilteredX11ErrorHandler));
+
+  XUngrabServer(xdisplay_);
+
+  // Set root window cursor. Host windows that don't define their own cursor
+  // will inherit the default cursor defined here.
+  XDefineCursor(xdisplay_, x_root_window_, ui::GetXCursor(XC_left_ptr));
+
+  for (size_t i = 0; i < nchildren; ++i)
+    RegisterNewTopLevel(xwindows.get()[i]);
+
+  HostWindowNeedsConfigure(client_->GetRootWindow());
+}
+
+void HostWindowManagerX11::RegisterNewTopLevel(::Window xwindow) {
+  gfx::Rect bounds(gfx::Point(-100, -100), gfx::Size(1, 1));
+  bool visible = false;
+  bool managed = false;
+
+  XWindowAttributes attributes;
+  // Ignore possible X error as we can't guarantee that host window exists.
+  xerror_ignore_queue.push(NextRequest(xdisplay_));
+  if (XGetWindowAttributes(xdisplay_, xwindow, &attributes)) {
+    int border_size = attributes.border_width * 2;
+    bounds = gfx::Rect(attributes.x,
+                       attributes.y,
+                       attributes.width + border_size,
+                       attributes.height + border_size);
+    visible = attributes.map_state == IsViewable;
+    managed = !attributes.override_redirect;
+  }
+
+  RegisterNewTopLevel(xwindow, bounds, managed);
+
+  if (visible) {
+    Window* window = native_windows_[xwindow];
+    DCHECK(window);
+    client_->OnHostWindowMovedOrResizedConstrained(
+        window, GetTargetBoundsInRootWindow(window));
+    client_->OnHostWindowVisibilityChanged(window, true);
+  }
+}
+
+void HostWindowManagerX11::RegisterNewTopLevel(
+    ::Window xwindow, const gfx::Rect bounds, bool managed) {
+  client::HostWindowManagerClient* client = client_;
+
+  // Add a HostWindowX11 for the root input window.
+  RootWindow* root_window = client->GetRootWindow();
+  if (xwindow == root_window->GetAcceleratedWidgetUsedForEvents()) {
+    top_level_windows_[xwindow] = new HostWindowX11(xwindow, NormalState);
+    return;
+  }
+
+  // Container input windows will already have a native mapping.
+  if (native_windows_.find(xwindow) != native_windows_.end()) {
+    Window* window = native_windows_[xwindow];
+
+    if (input_host_windows_.find(window) != input_host_windows_.end()) {
+      top_level_windows_[xwindow] = input_host_windows_[window];
+      return;
+    }
+  }
+
+  // This is foreign host window.
+  scoped_refptr<HostWindowX11> top_level;
+  bool decorated = false;
+
+  if (managed) {
+    top_level = new ManagedRedirectedHostWindowX11(
+        this, xwindow, bounds.size());
+    decorated = true;
+  } else {
+    top_level = new RedirectedHostWindowX11(this, xwindow, bounds.size());
+  }
+
+  // Create a native window.
+  Window* window = client->OnHostWindowCreated(bounds, decorated);
+  SetHostWindowDelegate(window, top_level);
+  top_level_windows_[xwindow] = top_level;
+
+  native_windows_[xwindow] = window;
+  host_windows_[window] = xwindow;
+}
+
+}  // namespace aura