use simpler gradient factories (in prep for removing SkUnitMapper param)

ui/native_theme/native_theme_base.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/native_theme/native_theme_base.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 587 matching lines @@
     startEndColors = kCheckboxGradientPressedColors;
   else if (state == kHovered)
     startEndColors = kCheckboxGradientHoveredColors;
   else if (state == kDisabled)
     startEndColors = kCheckboxGradientDisabledColors;
   else /* kNormal */
     startEndColors = kCheckboxGradientColors;
   SkColor colors[3] = {startEndColors[0], startEndColors[0], startEndColors[1]};
   skia::RefPtr<SkShader> shader = skia::AdoptRef(
       SkGradientShader::CreateLinear(
-          gradient_bounds, colors, NULL, 3, SkShader::kClamp_TileMode, NULL));
+          gradient_bounds, colors, NULL, 3, SkShader::kClamp_TileMode));
   SkPaint paint;
   paint.setAntiAlias(true);
   paint.setShader(shader.get());
   paint.setStyle(SkPaint::kFill_Style);
   canvas->drawRoundRect(skrect, borderRadius, borderRadius, paint);
   paint.setShader(NULL);
 
   // Draw the border.
   if (state == kHovered)
     paint.setColor(kCheckboxBorderHoveredColor);
@@ skipping 66 matching lines @@
   const int kDarkEnd = !kLightEnd;
   SkPoint gradient_bounds[2];
   gradient_bounds[kLightEnd].iset(rect.x(), rect.y());
   gradient_bounds[kDarkEnd].iset(rect.x(), kBottom - 1);
   SkColor colors[2];
   colors[0] = light_color;
   colors[1] = base_color;
 
   skia::RefPtr<SkShader> shader = skia::AdoptRef(
       SkGradientShader::CreateLinear(
-          gradient_bounds, colors, NULL, 2, SkShader::kClamp_TileMode, NULL));
+          gradient_bounds, colors, NULL, 2, SkShader::kClamp_TileMode));
   paint.setStyle(SkPaint::kFill_Style);
   paint.setAntiAlias(true);
   paint.setShader(shader.get());
 
   canvas->drawRoundRect(skrect, SkIntToScalar(1), SkIntToScalar(1), paint);
   paint.setShader(NULL);
 
   if (button.has_border) {
     int border_alpha = state == kHovered ? 0x80 : 0x55;
     if (button.is_focused) {
@@ skipping 356 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 ui