Make GetRootWindow() return a Window instead of a RootWindow.

ui/snapshot/snapshot_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 "ui/snapshot/snapshot.h"
 
 #include "base/logging.h"
 #include "base/safe_numerics.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkPixelRef.h"
@@ skipping 22 matching lines @@
 bool GrabWindowSnapshot(gfx::NativeWindow window,
                         std::vector<unsigned char>* png_representation,
                         const gfx::Rect& snapshot_bounds) {
   ui::Compositor* compositor = window->layer()->GetCompositor();
 
   gfx::RectF read_pixels_bounds = snapshot_bounds;
 
   // We must take into account the window's position on the desktop.
   read_pixels_bounds.Offset(
       window->GetBoundsInRootWindow().origin().OffsetFromOrigin());
-  aura::RootWindow* root_window = window->GetRootWindow();
-  if (root_window)
-    root_window->GetRootTransform().TransformRect(&read_pixels_bounds);
+  aura::WindowEventDispatcher* dispatcher = window->GetDispatcher();
+  if (dispatcher)
+    dispatcher->GetRootTransform().TransformRect(&read_pixels_bounds);
 
   gfx::Rect read_pixels_bounds_in_pixel =
       gfx::ToEnclosingRect(read_pixels_bounds);
 
   // Sometimes (i.e. when using Aero on Windows) the compositor's size is
   // smaller than the window bounds. So trim appropriately.
   read_pixels_bounds_in_pixel.Intersect(gfx::Rect(compositor->size()));
 
   DCHECK_LE(0, read_pixels_bounds.x());
   DCHECK_LE(0, read_pixels_bounds.y());
@@ skipping 25 matching lines @@
       bitmap.pixelRef()->pixels());
   gfx::PNGCodec::Encode(pixels, gfx::PNGCodec::FORMAT_BGRA,
                         gfx::Size(bitmap.width(), bitmap.height()),
                         base::checked_numeric_cast<int>(bitmap.rowBytes()),
                         true, std::vector<gfx::PNGCodec::Comment>(),
                         png_representation);
   return true;
 }
 
 }  // namespace ui