exo: Fix dragging edge cases

components/exo/shell_surface.cc

Index: components/exo/shell_surface.cc
diff --git a/components/exo/shell_surface.cc b/components/exo/shell_surface.cc
index cf8cced1d4c8210fd0d2ee2a0262be8089afd467..d82efbfc17b277835dfcf0eb7dcc75121459dc1c 100644
--- a/components/exo/shell_surface.cc
+++ b/components/exo/shell_surface.cc
@@ -13,6 +13,7 @@
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm/window_state_delegate.h"
 #include "ash/common/wm_shell.h"
+#include "ash/wm/drag_window_resizer.h"
 #include "ash/wm/window_state_aura.h"
 #include "ash/wm/window_util.h"
 #include "base/logging.h"
@@ -21,6 +22,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "components/exo/display.h"
 #include "components/exo/surface.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/cursor_client.h"
@@ -186,6 +188,26 @@ class CustomWindowStateDelegate : public ash::wm::WindowStateDelegate,
   DISALLOW_COPY_AND_ASSIGN(CustomWindowStateDelegate);
 };
 
+class CustomWindowResizer : public ash::WindowResizer {
+ public:
+  explicit CustomWindowResizer(ash::wm::WindowState* window_state)
+      : WindowResizer(window_state), shell_(GetTarget()->GetShell()) {
+    shell_->LockCursor();
+  }
+
+  ~CustomWindowResizer() override { shell_->UnlockCursor(); }
+
+  // ash::WindowResizer:
+  void Drag(const gfx::Point& location, int event_flags) override {}
+  void CompleteDrag() override {}
+  void RevertDrag() override {}
+
+ private:
+  ash::WmShell* const shell_;
+
+  DISALLOW_COPY_AND_ASSIGN(CustomWindowResizer);
+};
+
 class ShellSurfaceWidget : public views::Widget {
  public:
   explicit ShellSurfaceWidget(ShellSurface* shell_surface)
@@ -332,18 +354,21 @@ ShellSurface::ScopedAnimationsDisabled::~ScopedAnimationsDisabled() {
 DEFINE_LOCAL_WINDOW_PROPERTY_KEY(std::string*, kApplicationIdKey, nullptr)
 DEFINE_LOCAL_WINDOW_PROPERTY_KEY(Surface*, kMainSurfaceKey, nullptr)
 
-ShellSurface::ShellSurface(Surface* surface,
+ShellSurface::ShellSurface(const Display& display,
+                           Surface* surface,
                            ShellSurface* parent,
                            const gfx::Rect& initial_bounds,
                            bool activatable,
                            int container)
-    : widget_(nullptr),
+    : display_(display),
+      widget_(nullptr),
       surface_(surface),
       parent_(parent ? parent->GetWidget()->GetNativeWindow() : nullptr),
       initial_bounds_(initial_bounds),
       activatable_(activatable),
       container_(container) {
   WMHelper::GetInstance()->AddActivationObserver(this);
+  WMHelper::GetInstance()->AddShellObserver(this);
   surface_->SetSurfaceDelegate(this);
   surface_->AddSurfaceObserver(this);
   surface_->window()->Show();
@@ -352,8 +377,9 @@ ShellSurface::ShellSurface(Surface* surface,
     parent_->AddObserver(this);
 }
 
-ShellSurface::ShellSurface(Surface* surface)
-    : ShellSurface(surface,
+ShellSurface::ShellSurface(const Display& display, Surface* surface)
+    : ShellSurface(display,
+                   surface,
                    nullptr,
                    gfx::Rect(),
                    true,
@@ -361,8 +387,7 @@ ShellSurface::ShellSurface(Surface* surface)
 
 ShellSurface::~ShellSurface() {
   DCHECK(!scoped_configure_);
-  if (resizer_)
-    EndDrag(false /* revert */);
+  EndDragOrMove(false /* revert */);
   if (widget_) {
     ash::wm::GetWindowState(widget_->GetNativeWindow())->RemoveObserver(this);
     widget_->GetNativeWindow()->RemoveObserver(this);
@@ -371,6 +396,7 @@ ShellSurface::~ShellSurface() {
     widget_->CloseNow();
   }
   WMHelper::GetInstance()->RemoveActivationObserver(this);
+  WMHelper::GetInstance()->RemoveShellObserver(this);
   if (parent_)
     parent_->RemoveObserver(this);
   if (surface_) {
@@ -470,6 +496,41 @@ void ShellSurface::Restore() {
   widget_->Restore();
 }
 
+void ShellSurface::SetMoving() {
+  TRACE_EVENT0("exo", "ShellSurface::SetMoving");
+
+  if (move_resizer_)
+    return;
+
+  ash::wm::WindowState* const window_state =
+      ash::wm::GetWindowState(widget_->GetNativeWindow());
+
+  DCHECK(!window_state->drag_details());
+  window_state->CreateDragDetails(GetMouseLocation(), HTCAPTION,
+                                  aura::client::WINDOW_MOVE_SOURCE_MOUSE);
+
+  // The resizer renders phantom windows, but does not control window movement.
+  move_resizer_.reset(ash::DragWindowResizer::Create(
+      new CustomWindowResizer(window_state), window_state));
+
+  surface_->window()->SetCapture();
+}
+
+void ShellSurface::UnsetMoving(bool revert) {
+  TRACE_EVENT1("exo", "ShellSurface::UnsetMoving", "revert", revert);
+
+  if (!move_resizer_)
+    return;
+
+  if (revert)
+    move_resizer_->RevertDrag();
+  else
+    move_resizer_->CompleteDrag();
+
+  move_resizer_.reset();
+  surface_->window()->ReleaseCapture();
+}
+
 void ShellSurface::SetFullscreen(bool fullscreen) {
   TRACE_EVENT1("exo", "ShellSurface::SetFullscreen", "fullscreen", fullscreen);
 
@@ -684,9 +745,7 @@ void ShellSurface::OnSurfaceCommit() {
       }
     }
 
-    // Update surface bounds.
-    surface_->window()->SetBounds(
-        gfx::Rect(surface_origin, surface_->window()->layer()->size()));
+    UpdateSurfaceBounds();
 
     // Update surface scale.
     if (pending_scale_ != scale_) {
@@ -716,8 +775,7 @@ bool ShellSurface::IsSurfaceSynchronized() const {
 // SurfaceObserver overrides:
 
 void ShellSurface::OnSurfaceDestroying(Surface* surface) {
-  if (resizer_)
-    EndDrag(false /* revert */);
+  EndDragOrMove(false /* revert */);
   if (widget_)
     SetMainSurface(widget_->GetNativeWindow(), nullptr);
   surface->RemoveSurfaceObserver(this);
@@ -757,8 +815,7 @@ base::string16 ShellSurface::GetWindowTitle() const {
 }
 
 void ShellSurface::WindowClosing() {
-  if (resizer_)
-    EndDrag(true /* revert */);
+  EndDragOrMove(true /* revert */);
   SetEnabled(false);
   widget_ = nullptr;
   shadow_overlay_ = nullptr;
@@ -812,6 +869,8 @@ void ShellSurface::OnPreWindowStateTypeChange(
   ash::wm::WindowStateType new_type = window_state->GetStateType();
   if (ash::wm::IsMaximizedOrFullscreenOrPinnedWindowStateType(old_type) ||
       ash::wm::IsMaximizedOrFullscreenOrPinnedWindowStateType(new_type)) {
+    EndDragOrMove(false /* revert */);
+
     // When transitioning in/out of maximized or fullscreen mode we need to
     // make sure we have a configure callback before we allow the default
     // cross-fade animations. The configure callback provides a mechanism for
@@ -863,8 +922,7 @@ void ShellSurface::OnWindowBoundsChanged(aura::Window* window,
     pending_origin_config_offset_ += origin_offset;
     origin_ -= origin_offset;
 
-    surface_->window()->SetBounds(
-        gfx::Rect(GetSurfaceOrigin(), surface_->window()->layer()->size()));
+    UpdateSurfaceBounds();
 
     // The shadow size may be updated to match the widget. Change it back
     // to the shadow content size.
@@ -895,6 +953,9 @@ void ShellSurface::OnWindowActivated(
   if (!widget_)
     return;
 
+  if (lost_active == widget_->GetNativeWindow())
+    UnsetMoving(false /* revert */);
+
   if (gained_active == widget_->GetNativeWindow() ||
       lost_active == widget_->GetNativeWindow()) {
     DCHECK(activatable_);
@@ -904,6 +965,18 @@ void ShellSurface::OnWindowActivated(
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// WMHelper::ShellObserver overrides:
+
+void ShellSurface::OnOverviewModeStarted() {
+  EndDragOrMove(false /* revert */);
+  ignore_widget_bounds_changes_ = true;
+}
+
+void ShellSurface::OnOverviewModeEnded() {
+  ignore_widget_bounds_changes_ = false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // WMHelper::AccessibilityObserver overrides:
 
 void ShellSurface::OnAccessibilityModeChanged() {
@@ -1007,6 +1080,7 @@ void ShellSurface::CreateShellSurfaceWidget(ui::WindowShowState show_state) {
   params.parent =
       parent_ ? parent_ : WMHelper::GetInstance()->GetContainer(container_);
   params.bounds = initial_bounds_;
+  display_.ConvertFromVirtualToScreen(&params.bounds);
   bool activatable = activatable_;
   // ShellSurfaces in system modal container are only activatable if input
   // region is non-empty. See OnCommitSurface() for more details.
@@ -1120,16 +1194,10 @@ void ShellSurface::AttemptToStartDrag(int component) {
   if (widget_->GetNativeWindow()->HasCapture())
     return;
 
-  aura::Window* root_window = widget_->GetNativeWindow()->GetRootWindow();
-  gfx::Point drag_location =
-      root_window->GetHost()->dispatcher()->GetLastMouseLocationInRoot();
-  aura::Window::ConvertPointToTarget(
-      root_window, widget_->GetNativeWindow()->parent(), &drag_location);
-
   // Set the cursor before calling CreateWindowResizer(), as that will
   // eventually call LockCursor() and prevent the cursor from changing.
-  aura::client::CursorClient* cursor_client =
-      aura::client::GetCursorClient(root_window);
+  aura::client::CursorClient* cursor_client = aura::client::GetCursorClient(
+      widget_->GetNativeWindow()->GetRootWindow());
   DCHECK(cursor_client);
 
   switch (component) {
@@ -1166,7 +1234,7 @@ void ShellSurface::AttemptToStartDrag(int component) {
   }
 
   resizer_ = ash::CreateWindowResizer(
-      ash::WmWindowAura::Get(widget_->GetNativeWindow()), drag_location,
+      ash::WmWindowAura::Get(widget_->GetNativeWindow()), GetMouseLocation(),
       component, aura::client::WINDOW_MOVE_SOURCE_MOUSE);
   if (!resizer_)
     return;
@@ -1208,6 +1276,13 @@ void ShellSurface::EndDrag(bool revert) {
   UpdateWidgetBounds();
 }
 
+void ShellSurface::EndDragOrMove(bool revert) {
+  if (resizer_)
+    EndDrag(revert);
+  else
+    UnsetMoving(revert);
+}
+
 bool ShellSurface::IsResizing() const {
   if (!resizer_)
     return false;
@@ -1227,8 +1302,12 @@ gfx::Point ShellSurface::GetSurfaceOrigin() const {
 
   // If initial bounds were specified then surface origin is always relative
   // to those bounds.
-  if (!initial_bounds_.IsEmpty())
-    return initial_bounds_.origin() - window_bounds.OffsetFromOrigin();
+  if (!initial_bounds_.IsEmpty()) {
+    gfx::Point origin = window_bounds.origin();
+    wm::ConvertPointToScreen(widget_->GetNativeWindow()->parent(), &origin);
+    display_.ConvertFromScreenToVirtual(&origin);
+    return initial_bounds_.origin() - origin.OffsetFromOrigin();
+  }
 
   gfx::Rect visible_bounds = GetVisibleBounds();
   switch (resize_component_) {
@@ -1270,15 +1349,15 @@ void ShellSurface::UpdateWidgetBounds() {
     return;
   }
 
-  // 2) When a window is being dragged.
-  if (IsResizing())
+  // 2) When a window is being dragged, or is being moved by the shell.
+  if (IsResizing() || ignore_widget_bounds_changes_)
     return;
 
   // Return early if there is pending configure requests.
   if (!pending_configs_.empty() || scoped_configure_)
     return;
 
-  gfx::Rect visible_bounds = GetVisibleBounds();
+  gfx::Rect visible_bounds = GetVisibleBounds();  // In virtual coordinates.
   gfx::Rect new_widget_bounds = visible_bounds;
 
   // Avoid changing widget origin unless initial bounds were specified and
@@ -1286,6 +1365,12 @@ void ShellSurface::UpdateWidgetBounds() {
   if (initial_bounds_.IsEmpty())
     new_widget_bounds.set_origin(widget_->GetWindowBoundsInScreen().origin());
 
+  else {
+    new_widget_bounds.set_origin(initial_bounds_.origin() +
+                                 visible_bounds.OffsetFromOrigin());
+    display_.ConvertFromVirtualToScreen(&new_widget_bounds);
+  }
+
   // Update widget origin using the surface origin if the current location of
   // surface is being anchored to one side of the widget as a result of a
   // resize operation.
@@ -1300,11 +1385,29 @@ void ShellSurface::UpdateWidgetBounds() {
   // should not result in a configure request.
   DCHECK(!ignore_window_bounds_changes_);
   ignore_window_bounds_changes_ = true;
-  if (widget_->GetWindowBoundsInScreen() != new_widget_bounds)
-    widget_->SetBounds(new_widget_bounds);
+  if (widget_->GetWindowBoundsInScreen() != new_widget_bounds) {
+    if (!move_resizer_) {
+      widget_->SetBounds(new_widget_bounds);
+      UpdateSurfaceBounds();
+    } else {
+      // Convert from screen to display coordinates.
+      gfx::Point origin = new_widget_bounds.origin();
+      wm::ConvertPointFromScreen(widget_->GetNativeWindow()->parent(), &origin);
+      new_widget_bounds.set_origin(origin);
+
+      // Move the window relative to the current display.
+      widget_->GetNativeWindow()->SetBounds(new_widget_bounds);
+      UpdateSurfaceBounds();
+
+      // Render phantom windows when beyond the current display.
+      move_resizer_->Drag(GetMouseLocation(), 0);
+    }
+  }
+
   ignore_window_bounds_changes_ = false;
+}
 
-  // A change to the widget size requires surface bounds to be re-adjusted.
+void ShellSurface::UpdateSurfaceBounds() {
   surface_->window()->SetBounds(
       gfx::Rect(GetSurfaceOrigin(), surface_->window()->layer()->size()));
 }
@@ -1320,10 +1423,11 @@ void ShellSurface::UpdateShadow() {
   } else {
     wm::SetShadowType(window, wm::SHADOW_TYPE_RECTANGULAR);
 
-    // TODO(oshima): Adjust the coordinates from client screen to
-    // chromeos screen when multi displays are supported.
     gfx::Point origin = window->bounds().origin();
     gfx::Point shadow_origin = shadow_content_bounds_.origin();
+
+    display_.ConvertFromVirtualToScreen(&shadow_origin);
+    wm::ConvertPointFromScreen(window->parent(), &shadow_origin);
     shadow_origin -= origin.OffsetFromOrigin();
     gfx::Rect shadow_bounds(shadow_origin, shadow_content_bounds_.size());
 
@@ -1397,4 +1501,13 @@ void ShellSurface::UpdateShadow() {
   }
 }
 
+gfx::Point ShellSurface::GetMouseLocation() const {
+  aura::Window* const root_window = widget_->GetNativeWindow()->GetRootWindow();
+  gfx::Point location =
+      root_window->GetHost()->dispatcher()->GetLastMouseLocationInRoot();
+  aura::Window::ConvertPointToTarget(
+      root_window, widget_->GetNativeWindow()->parent(), &location);
+  return location;
+}
+
 }  // namespace exo