Avoids releasing capture prematurily when dragging tabs from one to another browser window

chrome/browser/ui/views/tabs/tab_drag_controller.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 "chrome/browser/ui/views/tabs/tab_drag_controller.h"
 
 #include <math.h>
 #include <set>
 
 #include "base/auto_reset.h"
@@ skipping 144 matching lines @@
 // static
 const int TabDragController::kVerticalDetachMagnetism = 15;
 
 TabDragController::TabDragController()
     : detach_into_browser_(true),
       event_source_(EVENT_SOURCE_MOUSE),
       source_tabstrip_(NULL),
       attached_tabstrip_(NULL),
       screen_(NULL),
       host_desktop_type_(chrome::HOST_DESKTOP_TYPE_NATIVE),
+      use_aura_capture_policy_(false),
       offset_to_width_ratio_(0),
       old_focused_view_id_(
           views::ViewStorage::GetInstance()->CreateStorageID()),
       last_move_screen_loc_(0),
       started_drag_(false),
       active_(true),
       source_tab_index_(std::numeric_limits<size_t>::max()),
       initial_move_(true),
       detach_behavior_(DETACHABLE),
       move_behavior_(REORDER),
@@ skipping 54 matching lines @@
     EventSource event_source) {
   DCHECK(!tabs.empty());
   DCHECK(std::find(tabs.begin(), tabs.end(), source_tab) != tabs.end());
   source_tabstrip_ = source_tabstrip;
   was_source_maximized_ = source_tabstrip->GetWidget()->IsMaximized();
   was_source_fullscreen_ = source_tabstrip->GetWidget()->IsFullscreen();
   screen_ = gfx::Screen::GetScreenFor(
       source_tabstrip->GetWidget()->GetNativeView());
   host_desktop_type_ = chrome::GetHostDesktopTypeForNativeView(
       source_tabstrip->GetWidget()->GetNativeView());
+#if defined(OS_LINUX)
+  use_aura_capture_policy_ = true;
+#else
+  use_aura_capture_policy_ =
+      (host_desktop_type_ == chrome::HOST_DESKTOP_TYPE_ASH);
+#endif
   start_point_in_screen_ = gfx::Point(source_tab_offset, mouse_offset.y());
   views::View::ConvertPointToScreen(source_tab, &start_point_in_screen_);
   event_source_ = event_source;
   mouse_offset_ = mouse_offset;
   detach_behavior_ = detach_behavior;
   move_behavior_ = move_behavior;
   last_point_in_screen_ = start_point_in_screen_;
   last_move_screen_loc_ = start_point_in_screen_.x();
   initial_tab_positions_ = source_tabstrip->GetTabXCoordinates();
   if (detach_behavior == NOT_DETACHABLE)
@@ skipping 403 matching lines @@
                "point_in_screen", point_in_screen.ToString());
 
   if (!target_tabstrip) {
     DetachIntoNewBrowserAndRunMoveLoop(point_in_screen);
     return DRAG_BROWSER_RESULT_STOP;
   }
   if (is_dragging_window_) {
     // ReleaseCapture() is going to result in calling back to us (because it
     // results in a move). That'll cause all sorts of problems.  Reset the
     // observer so we don't get notified and process the event.
-    if (host_desktop_type_ == chrome::HOST_DESKTOP_TYPE_ASH) {
+    if (use_aura_capture_policy_) {
       move_loop_widget_->RemoveObserver(this);
       move_loop_widget_ = NULL;
     }
     views::Widget* browser_widget = GetAttachedBrowserWidget();
     // Need to release the drag controller before starting the move loop as it's
     // going to trigger capture lost, which cancels drag.
     attached_tabstrip_->ReleaseDragController();
     target_tabstrip->OwnDragController(this);
     // Disable animations so that we don't see a close animation on aero.
     browser_widget->SetVisibilityChangedAnimationsEnabled(false);
     // For aura we can't release capture, otherwise it'll cancel a gesture.
     // Instead we have to directly change capture.
-    if (host_desktop_type_ == chrome::HOST_DESKTOP_TYPE_ASH)
+    if (use_aura_capture_policy_)
       target_tabstrip->GetWidget()->SetCapture(attached_tabstrip_);
     else
       browser_widget->ReleaseCapture();
 #if defined(OS_WIN)
     // The Gesture recognizer does not work well currently when capture changes
     // while a touch gesture is in progress. So we need to manually transfer
     // gesture sequence and the GR's touch events queue to the new window. This
     // should really be done somewhere in capture change code and or inside the
     // GR. But we currently do not have a consistent way for doing it that would
     // work in all cases. Hence this hack.
     ui::GestureRecognizer::Get()->TransferEventsTo(
         browser_widget->GetNativeView(),
         target_tabstrip->GetWidget()->GetNativeView());
 #endif
 
     // The window is going away. Since the drag is still on going we don't want
     // that to effect the position of any windows.
     SetWindowPositionManaged(browser_widget->GetNativeView(), false);
 
+#if !defined(OS_LINUX) || defined(OS_CHROMEOS)
     // EndMoveLoop is going to snap the window back to its original location.
-    // Hide it so users don't see this.
+    // Hide it so users don't see this. Hiding a window in Linux aura causes
+    // it to lose capture so skip it.
     browser_widget->Hide();
+#endif
     browser_widget->EndMoveLoop();
 
     // Ideally we would always swap the tabs now, but on non-ash it seems that
     // running the move loop implicitly activates the window when done, leading
     // to all sorts of flicker. So, on non-ash, instead we process the move
     // after the loop completes. But on chromeos, we can do tab swapping now to
     // avoid the tab flashing issue(crbug.com/116329).
-    if (host_desktop_type_ == chrome::HOST_DESKTOP_TYPE_ASH) {
+    if (use_aura_capture_policy_) {
       is_dragging_window_ = false;
       Detach(DONT_RELEASE_CAPTURE);
       Attach(target_tabstrip, point_in_screen);
       // Move the tabs into position.
       MoveAttached(point_in_screen);
       attached_tabstrip_->GetWidget()->Activate();
     } else {
       tab_strip_to_attach_to_after_exit_ = target_tabstrip;
     }
 
@@ skipping 404 matching lines @@
   std::vector<gfx::Rect> drag_bounds = CalculateBoundsForDraggedTabs();
   OffsetX(GetAttachedDragPoint(point_in_screen).x(), &drag_bounds);
 
   gfx::Vector2d drag_offset;
   Browser* browser = CreateBrowserForDrag(
       attached_tabstrip_, point_in_screen, &drag_offset, &drag_bounds);
 #if defined(OS_WIN)
   gfx::NativeView attached_native_view =
     attached_tabstrip_->GetWidget()->GetNativeView();
 #endif
-  Detach(host_desktop_type_ == chrome::HOST_DESKTOP_TYPE_ASH ?
-         DONT_RELEASE_CAPTURE : RELEASE_CAPTURE);
+  Detach(use_aura_capture_policy_ ? DONT_RELEASE_CAPTURE : RELEASE_CAPTURE);
   BrowserView* dragged_browser_view =
       BrowserView::GetBrowserViewForBrowser(browser);
   views::Widget* dragged_widget = dragged_browser_view->GetWidget();
 #if defined(OS_WIN)
     // The Gesture recognizer does not work well currently when capture changes
     // while a touch gesture is in progress. So we need to manually transfer
     // gesture sequence and the GR's touch events queue to the new window. This
     // should really be done somewhere in capture change code and or inside the
     // GR. But we currently do not have a consistent way for doing it that would
     // work in all cases. Hence this hack.
@@ skipping 755 matching lines @@
     aura::Window* dragged_window =
         attached_tabstrip_->GetWidget()->GetNativeView();
     if (dragged_window)
       exclude.insert(dragged_window);
   }
   return GetLocalProcessWindowAtPoint(host_desktop_type_,
                                       screen_point,
                                       exclude);
 
 }