MacViews: Implement Tab Dragging

ui/views/cocoa/bridged_native_widget.mm

Index: ui/views/cocoa/bridged_native_widget.mm
diff --git a/ui/views/cocoa/bridged_native_widget.mm b/ui/views/cocoa/bridged_native_widget.mm
index 0ccff9d15a0fd3402ed9c1e613f6552cd7de2f62..d701b765ab7878552b4ede6103174715ab7bd77f 100644
--- a/ui/views/cocoa/bridged_native_widget.mm
+++ b/ui/views/cocoa/bridged_native_widget.mm
@@ -37,8 +37,12 @@
 
 extern "C" {
 
+typedef int32_t CGSWindow;
 typedef int32_t CGSConnection;
 CGSConnection _CGSDefaultConnection();
+OSStatus CGSGetWindowBounds(CGSConnection connection,
+                            CGSWindow window,
+                            CGRect* bounds);
 CGError CGSSetWindowBackgroundBlurRadius(CGSConnection connection,
                                          NSInteger windowNumber,
                                          int radius);
@@ -203,6 +207,13 @@ NSEvent* RepostEventIfHandledByWindow(NSEvent* ns_event) {
   // - any repost loop.
 
   if (repost_state == NONE) {
+    if (CGEventGetIntegerValueField([ns_event CGEvent],
+                                    kCGEventSourceUserData) ==
+        views::CocoaWindowMoveLoop::
+            kCocoaWindowMoveLoopSimulatedEventUserData) {
+      return ns_event;
+    }
+
     if (WindowWantsMouseDownReposted(ns_event)) {
       repost_state = EXPECTING_REPOST;
       reposted_event_number = event_number;
@@ -615,6 +626,76 @@ bool BridgedNativeWidget::HasCapture() {
   return mouse_capture_ && mouse_capture_->IsActive();
 }
 
+Widget::MoveLoopResult BridgedNativeWidget::RunMoveLoop(
+      const gfx::Vector2d& drag_offset) {
+  DCHECK(!HasCapture());
+  DCHECK(!window_move_loop_);
+
+  // First, position the window in the right place. The point |drag_offset|
+  // away from the top-left corner needs to be positioned under the mouse.
+  // TODO(tapted): Figure out why the toolkit-views drag controller doesn't get
+  // this right when it first initializes the Widget.
+  gfx::Point mouse_in_screen = gfx::Screen::GetScreen()->GetCursorScreenPoint();
+
+  // A window can't be moved vertically up out of the work area. Treat this case
+  // as if the mouse location is at the point it would be when the window first
+  // stopped moving. That is, vertically down such that the top edge of the
+  // window touches the menubar (or top of the screen in a dual-screen setup).
+  // Note on Mac we can assume that the y-coordinate of the work area origin is
+  // the bottom of the menu bar and not the Dock which doesn't affect window
+  // movement, but can reduce the work area on the bottom, left and right.
+  const gfx::Display display =
+      gfx::Screen::GetScreen()->GetDisplayNearestPoint(mouse_in_screen);
+  const int min_y = display.work_area().y() + drag_offset.y();
+  if (mouse_in_screen.y() < min_y)
+    mouse_in_screen.set_y(min_y);
+
+  gfx::Rect frame = gfx::ScreenRectFromNSRect([window_ frame]);
+  frame.set_x(mouse_in_screen.x() - drag_offset.x());
+  frame.set_y(mouse_in_screen.y() - drag_offset.y());
+  DCHECK_GE(frame.y(), display.work_area().y());
+
+  // After setting the frame to correct the initial offset, the drag controller
+  // may immediately want to quit when it's notified of the new bounds. So the
+  // MoveLoop must be set up before the call to setFrame.
+  window_move_loop_.reset(new CocoaWindowMoveLoop(this, mouse_in_screen));
+
+  const NSRect ns_frame = gfx::ScreenRectToNSRect(frame);
+  [window_ setFrame:ns_frame display:YES animate:NO];
+
+  // Setting the frame will call OnWidgetBoundsChanged(), which could result in
+  // a call to EndMoveLoop().
+  if (!window_move_loop_)
+    return Widget::MOVE_LOOP_SUCCESSFUL;
+
+  // Make sure WindowServer has caught up with moving the window, this is
+  // required in order to send the MouseDown click to the intended position.
+  // El Capitan would always replicate the old window coordinates when calling
+  // CGSGetWindowBounds().
+  // DetachToBrowserTabDragControllerTest.MacDetachesAndReattachesSecondTab will
+  // fail without the following NSRunLoop pass.
+  [[NSRunLoop currentRunLoop]
+      runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0]];
+  DCHECK(NSEqualRects(ns_frame, WindowServerFrame()));
+
+  return window_move_loop_->Run();
+
+  // |this| may be destroyed during the RunLoop, causing it to exit early.
+  // Even if that doesn't happen, CocoaWindowMoveLoop will clean itself up by
+  // calling EndMoveLoop(). So window_move_loop_ will always be null before the
+  // function returns. But don't DCHECK since |this| might not be valid.
+}
+
+void BridgedNativeWidget::EndMoveLoop() {
+  DCHECK(window_move_loop_);
+  window_move_loop_->End();
+  window_move_loop_.reset();
+}
+
+bool BridgedNativeWidget::IsRunMoveLoopActive() const {
+  return window_move_loop_.get();
+}
+
 void BridgedNativeWidget::SetNativeWindowProperty(const char* name,
                                                   void* value) {
   NSString* key = [NSString stringWithUTF8String:name];
@@ -636,6 +717,7 @@ void BridgedNativeWidget::SetCursor(NSCursor* cursor) {
 }
 
 void BridgedNativeWidget::OnWindowWillClose() {
+  DCHECK(!drag_run_loop_);
   if (parent_) {
     parent_->RemoveChildWindow(this);
     parent_ = nullptr;
@@ -733,6 +815,10 @@ void BridgedNativeWidget::OnSizeChanged() {
     [bridged_view_ updateWindowMask];
 }
 
+void BridgedNativeWidget::OnPositionChanged() {
+  native_widget_mac_->GetWidget()->OnNativeWidgetMove();
+}
+
 void BridgedNativeWidget::OnVisibilityChanged() {
   OnVisibilityChangedTo([window_ isVisible]);
 }
@@ -886,6 +972,15 @@ gfx::Rect BridgedNativeWidget::GetRestoredBounds() const {
   return gfx::ScreenRectFromNSRect([window_ frame]);
 }
 
+NSRect BridgedNativeWidget::WindowServerFrame() const {
+  CGRect bounds = NSZeroRect;
+  CGSGetWindowBounds(_CGSDefaultConnection(), [window_ windowNumber],
+                     &bounds);
+  NSRect rect = ScreenRectToNSRect(gfx::Rect(bounds));
+  rect.size = [window_ frame].size;
+  return rect;
+}
+
 void BridgedNativeWidget::CreateLayer(ui::LayerType layer_type,
                                       bool translucent) {
   DCHECK(bridged_view_);