MacViews: Implement Tab Dragging

chrome/browser/ui/views/tabs/tab_drag_controller.cc

Index: chrome/browser/ui/views/tabs/tab_drag_controller.cc
diff --git a/chrome/browser/ui/views/tabs/tab_drag_controller.cc b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
index eb5dd067822b015bd313fcb34c30eb42867f885c..8f3e9e81fb972a203289122d20975d75a6483c4d 100644
--- a/chrome/browser/ui/views/tabs/tab_drag_controller.cc
+++ b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
@@ -85,6 +85,15 @@ const int kStackedDistance = 36;
 // maximized size.
 const int kMaximizedWindowInset = 10;  // DIPs.
 
+// Whether a new browser window created during a drag is destroyed immediately
+// once it is associated with a new tab strip. If false, windows created during
+// the drag are destroyed only when the drag ends.
+#if 0 && defined(OS_MACOSX)

[tapted, 2016/03/01 08:11:58]

So, this doesn't work yet. It's fine for a follow-up (until then this constant
should be removed).

However, this really should be enabled on Mac. The drag and drop that occurs on
Aura is quite janky compared to the technique in Cocoa Chrome. We should
experiment to see if we can get it here.

[themblsha, 2016/03/09 17:40:22]

Done.

+const bool windows_destroy_during_drag = false;
+#else
+const bool windows_destroy_during_drag = true;
+#endif
+
 #if defined(USE_ASH)
 void SetWindowPositionManaged(gfx::NativeWindow window, bool value) {
   ash::wm::GetWindowState(window)->set_window_position_managed(value);
@@ -272,7 +281,12 @@ void TabDragController::Init(
   can_release_capture_ = false;
 #endif
   start_point_in_screen_ = gfx::Point(source_tab_offset, mouse_offset.y());
+  DLOG(INFO) << "TabDragController::Init/mouse offset -> point_in_window="
+      << mouse_offset.ToString() << " -> "
+      << start_point_in_screen_.ToString();
   views::View::ConvertPointToScreen(source_tab, &start_point_in_screen_);
+  DLOG(INFO) << " --> in screen=" << start_point_in_screen_.ToString();
+
   event_source_ = event_source;
   mouse_offset_ = mouse_offset;
   move_behavior_ = move_behavior;
@@ -344,10 +358,14 @@ void TabDragController::Drag(const gfx::Point& point_in_screen) {
   if (waiting_for_run_loop_to_exit_)
     return;
 
+  DLOG(INFO) << "Started_drag = " << started_drag_;
+
   if (!started_drag_) {
     if (!CanStartDrag(point_in_screen))
       return;  // User hasn't dragged far enough yet.
 
+    DLOG(INFO) << "STARTING!";
+
     // On windows SaveFocus() may trigger a capture lost, which destroys us.
     {
       base::WeakPtr<TabDragController> ref(weak_factory_.GetWeakPtr());
@@ -355,6 +373,7 @@ void TabDragController::Drag(const gfx::Point& point_in_screen) {
       if (!ref)
         return;
     }
+    DLOG(INFO) << "Starting drag";
     started_drag_ = true;
     Attach(source_tabstrip_, gfx::Point());
     if (static_cast<int>(drag_data_.size()) ==
@@ -523,13 +542,19 @@ bool TabDragController::CanStartDrag(const gfx::Point& point_in_screen) const {
   static const int kMinimumDragDistance = 10;
   int x_offset = abs(point_in_screen.x() - start_point_in_screen_.x());
   int y_offset = abs(point_in_screen.y() - start_point_in_screen_.y());
-  return sqrt(pow(static_cast<float>(x_offset), 2) +
+  bool result = sqrt(pow(static_cast<float>(x_offset), 2) +
               pow(static_cast<float>(y_offset), 2)) > kMinimumDragDistance;
+  DLOG(INFO) << start_point_in_screen_.ToString() << " , "
+             << point_in_screen.ToString();
+  DLOG(INFO) << "can start = " << result;
+  return result;
 }
 
 void TabDragController::ContinueDragging(const gfx::Point& point_in_screen) {
   TRACE_EVENT1("views", "TabDragController::ContinueDragging",
                "point_in_screen", point_in_screen.ToString());
+  DLOG(INFO) << "ContinueDragging... point_in_screen="
+             << point_in_screen.ToString();
 
   DCHECK(attached_tabstrip_);
 
@@ -607,6 +632,14 @@ TabDragController::DragBrowserToNewTabStrip(
     // going to trigger capture lost, which cancels drag.
     attached_tabstrip_->ReleaseDragController();
     target_tabstrip->OwnDragController(this);
+    if (!windows_destroy_during_drag) {
+      Detach(DONT_RELEASE_CAPTURE);
+      Attach(target_tabstrip, point_in_screen);
+      // Move the tabs into position.
+      // MoveAttached(point_in_screen);  // assumes !is_dragging_window_
+      return DRAG_BROWSER_RESULT_CONTINUE;
+    }
+
     // Disable animations so that we don't see a close animation on aero.
     browser_widget->SetVisibilityChangedAnimationsEnabled(false);
     if (can_release_capture_)
@@ -822,6 +855,7 @@ TabStrip* TabDragController::GetTargetTabStripForPoint(
                "point_in_screen", point_in_screen.ToString());
 
   if (move_only() && attached_tabstrip_) {
+    DLOG(INFO) << "MoveOnly";
     // move_only() is intended for touch, in which case we only want to detach
     // if the touch point moves significantly in the vertical distance.
     gfx::Rect tabstrip_bounds = GetViewScreenBounds(attached_tabstrip_);
@@ -889,6 +923,8 @@ void TabDragController::Attach(TabStrip* attached_tabstrip,
   std::vector<Tab*> tabs =
       GetTabsMatchingDraggedContents(attached_tabstrip_);
 
+  bool acquire_capture = true;
+
   if (tabs.empty()) {
     // Transitioning from detached to attached to a new tabstrip. Add tabs to
     // the new model.
@@ -928,6 +964,10 @@ void TabDragController::Attach(TabStrip* attached_tabstrip,
     }
 
     tabs = GetTabsMatchingDraggedContents(attached_tabstrip_);
+
+    // If the windows are kept, there's no need to re-acquire capture. Instead,
+    // the TabDragController remains in a MoveLoop.
+    acquire_capture = windows_destroy_during_drag;
   }
   DCHECK_EQ(tabs.size(), drag_data_.size());
   for (size_t i = 0; i < drag_data_.size(); ++i)
@@ -951,7 +991,8 @@ void TabDragController::Attach(TabStrip* attached_tabstrip,
   // Transfer ownership of us to the new tabstrip as well as making sure the
   // window has capture. This is important so that if activation changes the
   // drag isn't prematurely canceled.
-  attached_tabstrip_->GetWidget()->SetCapture(attached_tabstrip_);
+  if (acquire_capture)
+    attached_tabstrip_->GetWidget()->SetCapture(attached_tabstrip_);
   attached_tabstrip_->OwnDragController(this);
 }
 
@@ -1744,6 +1785,7 @@ Browser* TabDragController::CreateBrowserForDrag(
   SetWindowPositionManaged(browser->window()->GetNativeWindow(), false);
   // If the window is created maximized then the bounds we supplied are ignored.
   // We need to reset them again so they are honored.
+  DLOG(INFO) << "SetBounds -> " << new_bounds.ToString();
   browser->window()->SetBounds(new_bounds);
 
   return browser;