Add a Canvas::SaveAndUnscale() method for pixel-accurate drawing.

chrome/browser/ui/views/frame/browser_view.cc

 // Copyright 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/frame/browser_view.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 532 matching lines @@
 
 // static
 BrowserView* BrowserView::GetBrowserViewForBrowser(const Browser* browser) {
   return static_cast<BrowserView*>(browser->window());
 }
 
 // static
 void BrowserView::Paint1pxHorizontalLine(gfx::Canvas* canvas,
                                          SkColor color,
                                          const gfx::Rect& bounds) {
-  canvas->Save();
-  SkScalar scale_factor = 1.0f / canvas->image_scale();
-  canvas->sk_canvas()->scale(scale_factor, scale_factor);
-
-  gfx::RectF line_rect =
-      gfx::ScaleRect(gfx::RectF(bounds), canvas->image_scale());
-  line_rect.Inset(0, line_rect.height() - 1, 0, 0);
-
+  const float scale = canvas->SaveAndUnscale();
+  gfx::RectF rect(gfx::ScaleRect(gfx::RectF(bounds), scale));
+  rect.Inset(0, rect.height() - 1, 0, 0);
   SkPaint paint;
   paint.setColor(color);
-  canvas->sk_canvas()->drawRect(gfx::RectFToSkRect(line_rect), paint);
+  canvas->sk_canvas()->drawRect(gfx::RectFToSkRect(rect), paint);
   canvas->Restore();
 }
 
 void BrowserView::InitStatusBubble() {
   status_bubble_.reset(new StatusBubbleViews(contents_web_view_));
   contents_web_view_->SetStatusBubble(status_bubble_.get());
 }
 
 gfx::Rect BrowserView::GetToolbarBounds() const {
   gfx::Rect toolbar_bounds(toolbar_->bounds());
@@ skipping 2060 matching lines @@
   return immersive_mode_controller()->IsEnabled();
 }
 
 views::Widget* BrowserView::GetBubbleAssociatedWidget() {
   return GetWidget();
 }
 
 gfx::Rect BrowserView::GetTopContainerBoundsInScreen() {
   return top_container_->GetBoundsInScreen();
 }