Use a direct include of strings headers in ui/, part 1.

ui/base/ime/text_input_client.h

 // 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.
 
 #ifndef UI_BASE_IME_TEXT_INPUT_CLIENT_H_
 #define UI_BASE_IME_TEXT_INPUT_CLIENT_H_
 
 #include "base/basictypes.h"
 #include "base/i18n/rtl.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/base/ime/composition_text.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/base/range/range.h"
 #include "ui/base/ui_export.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Rect;
 }
 
@@ skipping 117 matching lines @@
   virtual void ExtendSelectionAndDelete(size_t before, size_t after) = 0;
 
   // Ensure the caret is within |rect|.  |rect| is in screen coordinates and
   // may extend beyond the bounds of this TextInputClient.
   virtual void EnsureCaretInRect(const gfx::Rect& rect) = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_TEXT_INPUT_CLIENT_H_