ui: Replace a use of ExtractImageRep with a canvas SaveLayer

chrome/browser/ui/views/tabs/tab.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/tabs/tab.h"
 
 #include <stddef.h>
 #include <limits>
 #include <utility>
 
@@ skipping 1257 matching lines @@
           gfx::RectF(width() * scale, height() * scale - 1));
     }
     flags.setColor(controller_->GetToolbarTopSeparatorColor());
     stroke_canvas->DrawPath(stroke, flags);
   }
 }
 
 void Tab::PaintPinnedTabTitleChangedIndicatorAndIcon(
     gfx::Canvas* canvas,
     const gfx::Rect& favicon_draw_bounds) {
+  const float kIndicatorCropRadius = 4.5f;

[sky, 2017/04/04 22:02:41]

Is there a reason to move these from where they were? I prefer keeping the
variables close to where they are used.

[danakj, 2017/04/04 22:10:44]

Oh, putting them together shows their relationship clearly, I can put them back
then.

I did the math for RTL but didn't run it, I'll give it a try.

+  const int kIndicatorRadius = 3;
+
   // The pinned tab title changed indicator consists of two parts:
   // . a clear (totally transparent) part over the bottom right (or left in rtl)
-  //   of the favicon. This is done by drawing the favicon to a canvas, then
+  //   of the favicon. This is done by drawing the favicon to a layer, then
   //   drawing the clear part on top of the favicon.
   // . a circle in the bottom right (or left in rtl) of the favicon.
   if (!favicon_.isNull()) {
-    const float kIndicatorCropRadius = 4.5;
-    gfx::Canvas icon_canvas(gfx::Size(gfx::kFaviconSize, gfx::kFaviconSize),
-                            canvas->image_scale(), false);
-    icon_canvas.DrawImageInt(favicon_, 0, 0);
+    canvas->SaveLayerAlpha(0xff);
+    canvas->DrawImageInt(favicon_, 0, 0, favicon_draw_bounds.width(),
+                         favicon_draw_bounds.height(), favicon_draw_bounds.x(),
+                         favicon_draw_bounds.y(), favicon_draw_bounds.width(),
+                         favicon_draw_bounds.height(), false);
     cc::PaintFlags clear_flags;
     clear_flags.setAntiAlias(true);
     clear_flags.setBlendMode(SkBlendMode::kClear);
-    const int circle_x = base::i18n::IsRTL() ? 0 : gfx::kFaviconSize;
-    icon_canvas.DrawCircle(gfx::PointF(circle_x, gfx::kFaviconSize),
-                           kIndicatorCropRadius, clear_flags);
-    canvas->DrawImageInt(gfx::ImageSkia(icon_canvas.ExtractImageRep()), 0, 0,
-                         favicon_draw_bounds.width(),
-                         favicon_draw_bounds.height(), favicon_draw_bounds.x(),
-                         favicon_draw_bounds.y(), favicon_draw_bounds.width(),
-                         favicon_draw_bounds.height(), false);
+    int circle_x =
+        favicon_draw_bounds.x() + (base::i18n::IsRTL() ? 0 : gfx::kFaviconSize);
+    int circle_y = favicon_draw_bounds.y() + gfx::kFaviconSize;
+    canvas->DrawCircle(gfx::Point(circle_x, circle_y), kIndicatorCropRadius,
+                       clear_flags);
+    canvas->Restore();
   }
 
   // Draws the actual pinned tab title changed indicator.
-  const int kIndicatorRadius = 3;
   cc::PaintFlags indicator_flags;
   indicator_flags.setColor(GetNativeTheme()->GetSystemColor(
       ui::NativeTheme::kColorId_ProminentButtonColor));
   indicator_flags.setAntiAlias(true);
   const int indicator_x = GetMirroredXWithWidthInView(
       favicon_bounds_.right() - kIndicatorRadius, kIndicatorRadius * 2);
   const int indicator_y = favicon_bounds_.bottom() - kIndicatorRadius;
   canvas->DrawCircle(gfx::Point(indicator_x + kIndicatorRadius,
                                 indicator_y + kIndicatorRadius),
                      kIndicatorRadius, indicator_flags);
@@ skipping 173 matching lines @@
   gfx::Rect bounds = favicon_bounds_;
   if (bounds.IsEmpty())
     return;
 
   // Extends the area to the bottom when the crash animation is in progress.
   if (crash_icon_animation_->is_animating())
     bounds.set_height(height() - bounds.y());
   bounds.set_x(GetMirroredXForRect(bounds));
   SchedulePaintInRect(bounds);
 }