Add a new GetSystemColor method to native theme.

ui/gfx/native_theme_base.cc

 // Copyright (c) 2011 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/gfx/native_theme_base.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "grit/gfx_resources.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace gfx {
 
+namespace {
+// Hardcoded colors for use when there is no system theme (Aura, ChromeOS).
+const SkColor kDefaultDialogBackgroundColor = SkColorSetRGB(200, 200, 200);
+}
+
 unsigned int NativeThemeBase::button_length_ = 14;
 #if defined(TOUCH_UI)
 unsigned int NativeThemeBase::scrollbar_width_ = 0;
 #else
 unsigned int NativeThemeBase::scrollbar_width_ = 15;
 #endif
 
 // These are the default dimensions of radio buttons and checkboxes.
 static const int kCheckboxAndRadioWidth = 13;
 static const int kCheckboxAndRadioHeight = 13;
@@ skipping 21 matching lines @@
 
   return color_utils::HSLToSkColor(adjusted, alpha);
 }
 
 NativeThemeBase::NativeThemeBase() {
 }
 
 NativeThemeBase::~NativeThemeBase() {
 }
 
+// This implementation returns hardcoded colors. It's used by NativeThemeAura
+// and NativeThemeChromeos and overridden by NativeThemeGtk.
+SkColor NativeThemeBase::GetSystemColor(ColorId color_id) const {
+  switch (color_id) {
+    case kDialogBackgroundColorId:
+      return kDefaultDialogBackgroundColor;
+    default:
+      NOTREACHED() << "Invalid color_id: " << color_id;
+      break;
+  }
+  return kColorYouShouldNeverSee;
+}
+
 gfx::Size NativeThemeBase::GetPartSize(Part part,
                                        State state,
                                        const ExtraParams& extra) const {
   switch (part) {
     // Please keep these in the order of NativeTheme::Part.
     case kCheckbox:
       return gfx::Size(kCheckboxAndRadioWidth, kCheckboxAndRadioHeight);
     case kInnerSpinButton:
       return gfx::Size(scrollbar_width_, 0);
     case kMenuList:
@@ skipping 915 matching lines @@
   SkScalar min_diff = Clamp((hsv1[1] + hsv2[1]) * 1.2f, 0.28f, 0.5f);
   SkScalar diff = Clamp(fabs(hsv1[2] - hsv2[2]) / 2, min_diff, 0.5f);
 
   if (hsv1[2] + hsv2[2] > 1.0)
     diff = -diff;
 
   return SaturateAndBrighten(hsv2, -0.2f, diff);
 }
 
 }  // namespace gfx