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..db5912516131f1df393f5c3c760c0edce35f5dfe 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)
+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);
@@ -381,7 +390,7 @@ void TabDragController::Drag(const gfx::Point& point_in_screen) {
                                          &drag_bounds);
         widget->SetVisibilityChangedAnimationsEnabled(true);
       }
-      RunMoveLoop(GetWindowOffset(point_in_screen));
+      RunMoveLoop(GetWindowOffset(start_point_in_screen_));

[themblsha, 2016/03/03 17:56:51]

Without this fix the first mouse move after pressing the button won't actually
move the window, only the second mouse move will.

This fix has the side effect that now window moves will work even with NSEvents,
that's why I've added an intermediate step and carefully check for the resulting
window bounds.

       return;
     }
   }
@@ -523,8 +532,9 @@ 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;
+  return result;
 }
 
 void TabDragController::ContinueDragging(const gfx::Point& point_in_screen) {
@@ -607,6 +617,14 @@ 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_)
@@ -889,6 +907,8 @@ 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 +948,10 @@ 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 +975,8 @@ 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);
 }