Change name of NativeTheme::instance() to make it clear it's web only.

ui/views/button_drag_utils.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 "ui/views/button_drag_utils.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/dragdrop/drag_utils.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 29 matching lines @@
                   const base::string16& title,
                   const gfx::ImageSkia& icon,
                   const gfx::Point* press_pt,
                   ui::OSExchangeData* data,
                   views::Widget* widget) {
   // Create a button to render the drag image for us.
   views::LabelButton button(NULL,
                             title.empty() ? base::UTF8ToUTF16(url.spec())
                                           : title);
   button.SetTextSubpixelRenderingEnabled(false);
-  const ui::NativeTheme* theme =
-      widget ? widget->GetNativeTheme() : ui::NativeTheme::instance();

[Evan Stade, 2015/11/19 23:29:14]

I looked at the call sites and I think |widget| is always non null. Exercising
the code (dragging from the location icon or url text) likewise worked fine.

+  const ui::NativeTheme* theme = widget->GetNativeTheme();
   button.SetTextColor(views::Button::STATE_NORMAL,
       theme->GetSystemColor(ui::NativeTheme::kColorId_LabelEnabledColor));
   gfx::ShadowValues shadows(
       10,
       gfx::ShadowValue(gfx::Vector2d(0, 0), 1.0f,
                        theme->GetSystemColor(
                            ui::NativeTheme::kColorId_LabelBackgroundColor)));
   button.SetTextShadows(shadows);
   button.SetMaxSize(gfx::Size(kLinkDragImageMaxWidth, 0));
   if (icon.isNull()) {
@@ skipping 13 matching lines @@
     press_point = gfx::Vector2d(prefsize.width() / 2, prefsize.height() / 2);
 
   // Render the image.
   scoped_ptr<gfx::Canvas> canvas(
       views::GetCanvasForDragImage(widget, prefsize));
   button.Paint(ui::CanvasPainter(canvas.get(), 1.f).context());
   drag_utils::SetDragImageOnDataObject(*canvas, press_point, data);
 }
 
 }  // namespace button_drag_utils