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

ui/views/painter.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/painter.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 133 matching lines @@
 void GradientPainter::Paint(gfx::Canvas* canvas, const gfx::Size& size) {
   SkPaint paint;
   SkPoint p[2];
   p[0].iset(0, 0);
   if (horizontal_)
     p[1].iset(size.width(), 0);
   else
     p[1].iset(0, size.height());
 
   skia::RefPtr<SkShader> s = skia::AdoptRef(SkGradientShader::CreateLinear(
-      p, colors_.get(), pos_.get(), count_, SkShader::kClamp_TileMode, NULL));
+      p, colors_.get(), pos_.get(), count_, SkShader::kClamp_TileMode));
   paint.setStyle(SkPaint::kFill_Style);
   paint.setShader(s.get());
 
   canvas->sk_canvas()->drawRectCoords(SkIntToScalar(0), SkIntToScalar(0),
                                       SkIntToScalar(size.width()),
                                       SkIntToScalar(size.height()), paint);
 }
 
 // ImagePainter ---------------------------------------------------------------
 
@@ skipping 149 matching lines @@
   canvas->DrawImageInt(*images_[LEFT], 0, 0);
   canvas->DrawImageInt(*images_[RIGHT], size.width() - images_[RIGHT]->width(),
                        0);
   canvas->TileImageInt(
       *images_[CENTER], images_[LEFT]->width(), 0,
       size.width() - images_[LEFT]->width() - images_[RIGHT]->width(),
       images_[LEFT]->height());
 }
 
 }  // namespace views