Update WM shadows for MD.

ash/common/frame/default_header_painter.cc

 // Copyright 2014 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 "ash/common/frame/default_header_painter.h"
 
 #include "ash/common/ash_layout_constants.h"
 #include "ash/common/frame/caption_buttons/frame_caption_button_container_view.h"
 #include "ash/common/frame/header_painter_util.h"
 #include "base/debug/leak_annotations.h"
@@ skipping 125 matching lines @@
   }
 
   int corner_radius = (frame_->IsMaximized() || frame_->IsFullscreen())
                           ? 0
                           : HeaderPainterUtil::GetTopCornerRadiusWhenRestored();
 
   SkPaint paint;
   int active_alpha = activation_animation_->CurrentValueBetween(0, 255);
   paint.setColor(color_utils::AlphaBlend(active_frame_color_,
                                          inactive_frame_color_, active_alpha));
-
+  paint.setAntiAlias(true);

[James Cook, 2016/12/05 23:38:35]

Why does this now require AA?

[Evan Stade, 2016/12/06 00:53:21]

It should have always had AA, but it wasn't particularly noticeable because
there used to be a border stroke superimposed over the corner and that stroke
did have AA. Now there's no stroke, just a shadow, so the jaggedness (and
asymmetry of left and right corners) looks pretty bad.

   TileRoundRect(canvas, paint, GetLocalBounds(), corner_radius);
 
   if (!frame_->IsMaximized() && !frame_->IsFullscreen() &&
       mode_ == MODE_INACTIVE && !UsesCustomFrameColors()) {
     PaintHighlightForInactiveRestoredWindow(canvas);
   }
   if (frame_->widget_delegate()->ShouldShowWindowTitle())
     PaintTitleBar(canvas);
   if (!UsesCustomFrameColors())
     PaintHeaderContentSeparator(canvas);
@@ skipping 159 matching lines @@
   return HeaderPainterUtil::GetTitleBounds(
       left_header_view_, caption_button_container_, GetTitleFontList());
 }
 
 bool DefaultHeaderPainter::UsesCustomFrameColors() const {
   return active_frame_color_ != kDefaultFrameColor ||
          inactive_frame_color_ != kDefaultFrameColor;
 }
 
 }  // namespace ash