Snap non toplevel dialog windows to pixel boundary.

components/constrained_window/constrained_window_views.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 "components/constrained_window/constrained_window_views.h"
 
 #include <algorithm>
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "components/constrained_window/constrained_window_views_client.h"
 #include "components/guest_view/browser/guest_view_base.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "components/web_modal/web_contents_modal_dialog_manager_delegate.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/views/border.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_observer.h"
 #include "ui/views/window/dialog_delegate.h"
 
 #if defined(OS_MACOSX)
 #import "components/constrained_window/native_web_contents_modal_dialog_manager_views_mac.h"
 #endif
 
+#if defined(USE_AURA)
+#include "ui/aura/window.h"
+#include "ui/compositor/dip_util.h"
+#endif
+
 using web_modal::ModalDialogHost;
 using web_modal::ModalDialogHostObserver;
 
 namespace constrained_window {
 namespace {
 
 ConstrainedWindowViewsClient* constrained_window_views_client = nullptr;
 
 // The name of a key to store on the window handle to associate
 // WidgetModalDialogHostObserverViews with the Widget.
@@ skipping 82 matching lines @@
     const display::Display display =
         display::Screen::GetScreen()->GetDisplayNearestView(
             dialog_host->GetHostView());
     const gfx::Rect work_area = display.work_area();
     if (!work_area.Contains(display_rect))
       display_rect.AdjustToFit(work_area);
     position = display_rect.origin();
   }
 
   widget->SetBounds(gfx::Rect(position, size));
+
+#if defined(USE_AURA)
+  if (!widget->is_top_level()) {
+    // Toplevel windows are automatiacally snapped, but CHILD windows
+    // may not. If it's not toplevel, snap the widget's layer to pixel
+    // based on the parent toplevel window, which should be snapped.
+    aura::Window* window = widget->GetNativeWindow();

[msw, 2017/07/05 20:16:42]

nit: use gfx::NativeView and GetNativeView or inline GetNativeView.

[oshima, 2017/07/07 18:11:30]

Done

+    views::Widget* toplevel =
+        views::Widget::GetTopLevelWidgetForNativeView(window->parent());
+    ui::SnapLayerToPhysicalPixelBoundary(toplevel->GetLayer(),
+                                         widget->GetLayer());
+  }
+#endif
 }
 
 }  // namespace
 
 // static
 void SetConstrainedWindowViewsClient(
     std::unique_ptr<ConstrainedWindowViewsClient> new_client) {
   delete constrained_window_views_client;
   constrained_window_views_client = new_client.release();
 }
@@ skipping 101 matching lines @@
     DCHECK_EQ(parent_view, host->GetHostView());
     ModalDialogHostObserver* dialog_host_observer =
         new WidgetModalDialogHostObserverViews(
             host, widget, kWidgetModalDialogHostObserverViewsKey);
     dialog_host_observer->OnPositionRequiresUpdate();
   }
   return widget;
 }
 
 }  // namespace constrained window