cpplint: Update Google Style Guide's URL

The link to https://google-styleguide.googlecode.com/svn/trunk/cppguide.xml is
no longer available. Point to GitHub instead.

Change-Id: I5a1010b42bd2e70348ae7ca6c5783d65520ff565
Reviewed-on: https://chromium-review.googlesource.com/488602Reviewed-by: Aaron Gable <agable@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>

cpplint.py

@@ -62,7 +62,7 @@ Syntax: cpplint.py [--verbose=#] [--output=vs7] [--filter=-x,+y,...]
         <file> [file] ...
 
   The style guidelines this tries to follow are those in
-    https://google-styleguide.googlecode.com/svn/trunk/cppguide.xml
+    https://google.github.io/styleguide/cppguide.html
 
   Every problem is given a confidence score from 1-5, with 5 meaning we are
   certain of the problem, and 1 meaning it could be a legitimate construct.
@@ -2925,7 +2925,7 @@ def CheckForFunctionLengths(filename, clean_lines, linenum,
   """Reports for long function bodies.
 
   For an overview why this is done, see:
-  https://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Write_Short_Functions
+  https://google.github.io/styleguide/cppguide.html#Write_Short_Functions
 
   Uses a simplistic algorithm assuming other style guidelines
   (especially spacing) are followed.
@@ -4726,7 +4726,7 @@ def CheckLanguage(filename, clean_lines, linenum, file_extension,
       and line[-1] != '\\'):
     error(filename, linenum, 'build/namespaces', 4,
           'Do not use unnamed namespaces in header files.  See '
-          'https://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Namespaces'
+          'https://google.github.io/styleguide/cppguide.html#Namespaces'
           ' for more information.')