Use ScaleToEnclosingRect when converting the viewport to window.

content/renderer/render_widget.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/renderer/render_widget.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 1497 matching lines @@
     return;
   }
   composition_character_bounds_ = character_bounds;
   composition_range_ = range;
   Send(new InputHostMsg_ImeCompositionRangeChanged(
       routing_id(), composition_range_, composition_character_bounds_));
 }
 
 void RenderWidget::convertViewportToWindow(blink::WebRect* rect) {
   if (IsUseZoomForDSFEnabled()) {
-    float reverse = 1 / GetOriginalDeviceScaleFactor();
     // TODO(oshima): We may need to allow pixel precision here as the the
     // anchor element can be placed at half pixel.
-    gfx::Rect window_rect =
-        gfx::ScaleToEnclosedRect(gfx::Rect(*rect), reverse);
-    rect->x = window_rect.x();
-    rect->y = window_rect.y();
-    rect->width = window_rect.width();
-    rect->height = window_rect.height();
+    *rect =
+        gfx::ScaleToEnclosingRect(*rect, 1.f / GetOriginalDeviceScaleFactor());
   }
 }
 
 void RenderWidget::convertWindowToViewport(blink::WebFloatRect* rect) {
   if (IsUseZoomForDSFEnabled()) {
     rect->x *= GetOriginalDeviceScaleFactor();
     rect->y *= GetOriginalDeviceScaleFactor();
     rect->width *= GetOriginalDeviceScaleFactor();
     rect->height *= GetOriginalDeviceScaleFactor();
   }
@@ skipping 528 matching lines @@
 void RenderWidget::requestPointerUnlock() {
   mouse_lock_dispatcher_->UnlockMouse(webwidget_mouse_lock_target_.get());
 }
 
 bool RenderWidget::isPointerLocked() {
   return mouse_lock_dispatcher_->IsMouseLockedTo(
       webwidget_mouse_lock_target_.get());
 }
 
 }  // namespace content