Align web content's layer to toplevel window instead of root on ash

content/browser/renderer_host/render_widget_host_view_aura.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 "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 44 matching lines @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_observer.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/compositor_vsync_manager.h"
+#include "ui/compositor/dip_util.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/gestures/gesture_recognizer.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/wm/public/activation_client.h"
@@ skipping 1536 matching lines @@
     float device_scale_factor) {
   if (!host_)
     return;
 
   UpdateScreenInfo(window_);
 
   const gfx::Display display = gfx::Screen::GetScreenFor(window_)->
       GetDisplayNearestWindow(window_);
   DCHECK_EQ(device_scale_factor, display.device_scale_factor());
   current_cursor_.SetDisplayInfo(display);
+  SnapToPhysicalPixelBoundary();
 }
 
 void RenderWidgetHostViewAura::OnWindowDestroying(aura::Window* window) {
 #if defined(OS_WIN)
   HWND parent = NULL;
   // If the tab was hidden and it's closed, host_->is_hidden would have been
   // reset to false in RenderWidgetHostImpl::RendererExited.
   if (!window_->GetRootWindow() || host_->is_hidden()) {
     parent = ui::GetHiddenWindow();
   } else {
@@ skipping 613 matching lines @@
   else if (!overscroll_controller_)
     overscroll_controller_.reset(new OverscrollController());
 }
 
 void RenderWidgetHostViewAura::SnapToPhysicalPixelBoundary() {
   // The top left corner of our view in window coordinates might not land on a
   // device pixel boundary if we have a non-integer device scale. In that case,
   // to avoid the web contents area looking blurry we translate the web contents
   // in the +x, +y direction to land on the nearest pixel boundary. This may
   // cause the bottom and right edges to be clipped slightly, but that's ok.
-  gfx::Point view_offset_dips = window_->GetBoundsInRootWindow().origin();
-  gfx::PointF view_offset = view_offset_dips;
-  view_offset.Scale(current_device_scale_factor_);
-  gfx::PointF view_offset_snapped(std::ceil(view_offset.x()),
-                                  std::ceil(view_offset.y()));
-
-  gfx::Vector2dF fudge = view_offset_snapped - view_offset;
-  fudge.Scale(1.0 / current_device_scale_factor_);
-  GetLayer()->SetSubpixelPositionOffset(fudge);
+  aura::Window* snapped = NULL;
+  // On desktop, use the root window. On alternative environment (ash),
+  // use the toplevel window which must be already snapped.
+  if (gfx::Screen::GetScreenFor(window_) !=
+      gfx::Screen::GetScreenByType(gfx::SCREEN_TYPE_ALTERNATE)) {
+    snapped = window_->GetRootWindow();
+  } else {
+    snapped = window_->GetToplevelWindow();
+  }
+  if (snapped && snapped != window_)
+    ui::SnapLayerToPhysicalPixelBoundary(snapped->layer(), window_->layer());
 }
 
 void RenderWidgetHostViewAura::InternalSetBounds(const gfx::Rect& rect) {
   if (HasDisplayPropertyChanged(window_))
     host_->InvalidateScreenInfo();
 
   SnapToPhysicalPixelBoundary();
   // Don't recursively call SetBounds if this bounds update is the result of
   // a Window::SetBoundsInternal call.
   if (!in_bounds_changed_)
@@ skipping 207 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewBase, public:
 
 // static
 void RenderWidgetHostViewBase::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content