update C++11 doc

site/dev/contrib/c++11.md

 C++11 in Skia
 =============
 
 Skia uses C++11.  But as a library, we are technically limited by what our
 clients support and what our build bots support.
 
 Skia may also be limited by restrictions we choose put on ourselves.  This
 document is not concerned with C++11 policy in Skia, only its technical
 feasibility.  This is about what we can use, a superset of what we may use.
 
 The gist:
 
--   C++11 the language as supported by GCC 4.7 or later is probably usable.
+-   C++11 the language as supported by GCC 4.7 or later is pretty usable.
+-   The C++11 standard library can generally be used, with some teething.
 -   If you break a bot, that feature is not usable.
--   The C++11 standard library can't generally be used.
 -   Local statics are not thread safe.
 
 
 Clients
 -------
 
 The clients we pay most attention to are Chrome, Android, Mozilla, and a few
 internal Google projects.
 
 Chrome builds with a recent Clang on Mac and Linux and with a recent MSVC on
 Windows.  These toolchains are new enough to not be the weak link to use any
-C++11 language feature.  But Chrome still supports Mac OS X 10.6, which does
-not ship with a C++11 standard library.  So [Chrome has banned the use of the
-C++11 standard library](http://chromium-cpp.appspot.com/).  Some header-only
-features are probably technically fine, but the Mac toolchain will prevent us
-from even trying at compile time as long as we target 10.6 as our minimum API
-level.
+C++11 language feature.
 
 Chrome intentionally disables thread-safe initialization of static variables,
-and MSVC doesn't support it at all, so we cannot rely on that.
+so we cannot rely on that.  Our bots disable this too, so keep an eye on TSAN.
 
-Android builds with either a recent GCC or a recent Clang.  They're generally
-not a weak link for C++11 language features.  Android's C++ standard library
-has always been a pain, but since we can't use it anyway (see Chrome), don't
-worry about it.
+Android builds with either a somewhat aged GCC or a recent Clang.  They're
+generally not a weak link for C++11 language features.  Android's C++ standard
+library had historically been a pain, but seems to work fine these days.
 
 Mozilla's current weak link is a minimum requirement of GCC 4.7.  Most features
 marked in red on Mozilla's C++11 [feature
 matrix](https://developer.mozilla.org/en-US/docs/Using_CXX_in_Mozilla_code) are
 marked that way because they arrived in GCC 4.8.  Their minimum-supported Clang
-and MSVC toolchains are great.  They also appear to ban the C++ standard
-library.
+and MSVC toolchains are pretty good, but MSVC 2013 will become the weak link soon.
 
 Internal Google projects tend to support C++11 completely, including the
 full C++11 standard library.
 
 
 Bots
 ----
 
 Most of our bots are pretty up-to-date: the Windows bots use MSVC 2013, the Mac
 bots a recent Clang, and the Linux bots GCC 4.8 or a recent Clang.  Our Android
 bots use a recent toolchain from Android (see above), and our Chrome bots use
 Chrome's toolchains (see above).  I'm not exactly sure what our Chrome OS bots
-are using, but they've never been a problem.
+are using.  They're probably our weak link right now, though problems are rare.
 
 I believe our bots' ability to use C++11 matches Mozilla's list nearly identically.