styleguide: Allow std::move for move semantics.

R=danakj@chromium.org, thakis@chromium.org

Review URL: https://codereview.chromium.org/1450013002

Cr-Commit-Position: refs/heads/master@{#359949}

Author: vmpstr

base/move.h

@@ -5,6 +5,8 @@
 #ifndef BASE_MOVE_H_
 #define BASE_MOVE_H_
 
+#include <utility>
+
 #include "base/compiler_specific.h"
 
 // Macro with the boilerplate that makes a type move-only in C++03.
@@ -222,13 +224,13 @@
   type(const type&); \
   void operator=(const type&); \
  public: \
-  type&& Pass() WARN_UNUSED_RESULT { return static_cast<type&&>(*this); } \
+  type&& Pass() WARN_UNUSED_RESULT { return std::move(*this); } \
   typedef void MoveOnlyTypeForCPP03; \
  private:
 
 #define TYPE_WITH_MOVE_CONSTRUCTOR_FOR_CPP_03(type) \
  public: \
-  type&& Pass() WARN_UNUSED_RESULT { return static_cast<type&&>(*this); } \
+  type&& Pass() WARN_UNUSED_RESULT { return std::move(*this); } \
  private:
 
 #endif  // BASE_MOVE_H_

styleguide/c++/c++11.html

@@ -288,6 +288,16 @@ <h2 id="whitelist">C++11 Allowed Library Features</h2>
 <td><a href="http://en.cppreference.com/w/cpp/utility/tuple/tie">std::tie</a></td>
 <td>General use of <code>std::tuple</code>, and <code>std::tie</code> for unpacking or multiple assignments is still not allowed. <a href="https://groups.google.com/a/chromium.org/d/topic/cxx/3DZ64dIMRTY/discussion">Discussion thread</a></td>
 </tr>
+
+<tr>
+<td>Move Semantics</td>
+<td><code>std::move()</code></td>
+<td>Facilitates efficient move operations</td>
+<td><a href="http://en.cppreference.com/w/cpp/utility/move">
+<code>std::move</code> reference</a></td>
+<td>Note: std::move() is allowed but writing your own move constructors is still only allowed in exceptional cases for now, see 'Rvalue References (and Move Semantics)'. <a href='https://groups.google.com/a/chromium.org/forum/#!topic/cxx/x_dWFxJFdbM'>Discussion thread</a></td>
+</tr>
+
 </tbody>
 </table>
 
@@ -808,15 +818,6 @@ <h3 id="blacklist_stdlib">C++11 Standard Library Features To Be Discussed</h3>
 <td></td>
 </tr>
 
-<tr>
-<td>Move Semantics</td>
-<td><code>std::move()</code></td>
-<td>Facilitates efficient move operations</td>
-<td><a href="http://en.cppreference.com/w/cpp/utility/move">
-<code>std::move</code> reference</a></td>
-<td></td>
-</tr>
-
 <tr>
 <td>Pointer Traits Class Template</td>
 <td><code>std::pointer_traits</code></td>