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

chrome/browser/ui/views/location_bar/location_bar_view.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 "chrome/browser/ui/views/location_bar/location_bar_view.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/i18n/rtl.h"
@@ skipping 1272 matching lines @@
     recorder.canvas()->DrawFocusRect(omnibox_view_->bounds());
 
   // Maximized popup windows don't draw the horizontal edges.  We implement this
   // by simply expanding the paint area outside the view by the edge thickness.
   gfx::Rect border_rect(GetContentsBounds());
   if (is_popup_mode_ && (GetHorizontalEdgeThickness() == 0))
     border_rect.Inset(-kPopupEdgeThickness, 0);
 
   if (ui::MaterialDesignController::IsModeMaterial()) {
     gfx::Canvas* canvas = recorder.canvas();
-    const float display_scale = canvas->image_scale();
-    canvas->Save();
-    SkScalar scale_factor = 1.0f / display_scale;
-    canvas->sk_canvas()->scale(scale_factor, scale_factor);
+    const float scale = canvas->SaveAndUnscale();
 
     SkPaint paint;
     paint.setStyle(SkPaint::Style::kStroke_Style);
     paint.setColor(SkColorSetARGB(0x40, 0x00, 0x00, 0x00));
     paint.setStrokeWidth(1);
     paint.setAntiAlias(true);
 
     const float kOffset = 0.5f;
     gfx::RectF border_rect_f(border_rect);
-    border_rect_f.Scale(display_scale);
+    border_rect_f.Scale(scale);
     gfx::InsetsF insets(kOffset, kOffset, kOffset, kOffset);
     border_rect_f.Inset(insets);
 
-    const SkScalar kCornerRadius = SkDoubleToScalar(2.5f * display_scale);
+    const SkScalar kCornerRadius = SkDoubleToScalar(2.5f * scale);
     canvas->sk_canvas()->drawRoundRect(gfx::RectFToSkRect(border_rect_f),
                                        kCornerRadius, kCornerRadius, paint);
     recorder.canvas()->Restore();
   } else {
     views::Painter::PaintPainterAt(recorder.canvas(), border_painter_.get(),
                                    border_rect);
   }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ skipping 100 matching lines @@
 
 void LocationBarView::ModelChanged(const SearchModel::State& old_state,
                                    const SearchModel::State& new_state) {
   const bool visible = !GetToolbarModel()->input_in_progress() &&
       new_state.voice_search_supported;
   if (mic_search_view_->visible() != visible) {
     mic_search_view_->SetVisible(visible);
     Layout();
   }
 }