cc: Move SkShader construction to a single spot in PaintShader

ui/native_theme/native_theme_base.cc

Index: ui/native_theme/native_theme_base.cc
diff --git a/ui/native_theme/native_theme_base.cc b/ui/native_theme/native_theme_base.cc
index 4a2fb957ed0f5ebfbc1249410ed20b8e6ee846ab..3b0a1243cb8f3d85a848919b519e57f48e2adf41 100644
--- a/ui/native_theme/native_theme_base.cc
+++ b/ui/native_theme/native_theme_base.cc
@@ -9,6 +9,7 @@
 
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/memory/ptr_util.h"
 #include "cc/paint/paint_flags.h"
 #include "cc/paint/paint_shader.h"
 #include "third_party/skia/include/core/SkPath.h"
@@ -601,11 +602,11 @@ SkRect NativeThemeBase::PaintCheckboxRadioCommon(
   SkColor colors[3] = {startEndColors[0], startEndColors[0], startEndColors[1]};
   cc::PaintFlags flags;
   flags.setAntiAlias(true);
-  flags.setShader(cc::WrapSkShader(SkGradientShader::MakeLinear(
-      gradient_bounds, colors, NULL, 3, SkShader::kClamp_TileMode)));
+  flags.setShader(base::MakeUnique<cc::PaintShader>(
+      gradient_bounds, colors, nullptr, 3, SkShader::kClamp_TileMode));
   flags.setStyle(cc::PaintFlags::kFill_Style);
   canvas->drawRoundRect(skrect, borderRadius, borderRadius, flags);
-  flags.setShader(NULL);
+  flags.setShader(nullptr);
 
   // Draw the border.
   if (state == kHovered)
@@ -682,11 +683,11 @@ void NativeThemeBase::PaintButton(cc::PaintCanvas* canvas,
 
   flags.setStyle(cc::PaintFlags::kFill_Style);
   flags.setAntiAlias(true);
-  flags.setShader(cc::WrapSkShader(SkGradientShader::MakeLinear(
-      gradient_bounds, colors, NULL, 2, SkShader::kClamp_TileMode)));
+  flags.setShader(base::MakeUnique<cc::PaintShader>(
+      gradient_bounds, colors, nullptr, 2, SkShader::kClamp_TileMode));
 
   canvas->drawRoundRect(skrect, SkIntToScalar(1), SkIntToScalar(1), flags);
-  flags.setShader(NULL);
+  flags.setShader(nullptr);
 
   if (button.has_border) {
     int border_alpha = state == kHovered ? 0x80 : 0x55;