Use a direct include of strings headers in ui/, part 3.

ui/views/controls/slider.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/controls/slider.h"
 
 #include "base/logging.h"
 #include "base/message_loop.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/base/animation/slide_animation.h"
 #include "ui/base/events/event.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
@@ skipping 299 matching lines @@
 void Slider::OnPaintFocusBorder(gfx::Canvas* canvas) {
   if (!focus_border_color_) {
     View::OnPaintFocusBorder(canvas);
   } else if (HasFocus() && (focusable() || IsAccessibilityFocusable())) {
     canvas->DrawRect(gfx::Rect(1, 1, width() - 3, height() - 3),
                      focus_border_color_);
   }
 }
 
 }  // namespace views