use DEFAULT_STATIC_FILES_PATH to find css files

get_ipython_package_dir() does not necessarily contain the files, e.g.
in distribution packages which share files with python3 in a different
folder.

IPython/nbconvert/preprocessors/csshtmlheader.py

@@ -1,105 +1,106
 """Module that pre-processes the notebook for export to HTML.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import io
 
 from IPython.utils import path
 
 from .base import Preprocessor
 
 from IPython.utils.traitlets import Unicode
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 class CSSHTMLHeaderPreprocessor(Preprocessor):
     """
     Preprocessor used to pre-process notebook for HTML output.  Adds IPython notebook
     front-end CSS and Pygments CSS to HTML output.
     """
 
     header = []
 
     highlight_class = Unicode('.highlight', config=True,
                               help="CSS highlight class identifier")
 
     def __init__(self, config=None, **kw):
         """
         Public constructor
         
         Parameters
         ----------
         config : Config
             Configuration file structure
         **kw : misc
             Additional arguments
         """
         
         super(CSSHTMLHeaderPreprocessor, self).__init__(config=config, **kw)
 
         if self.enabled :
             self._regen_header()
 
 
     def preprocess(self, nb, resources):
         """Fetch and add CSS to the resource dictionary
 
         Fetch CSS from IPython and Pygments to add at the beginning
         of the html files.  Add this css in resources in the 
         "inlining.css" key
         
         Parameters
         ----------
         nb : NotebookNode
             Notebook being converted
         resources : dictionary
             Additional resources used in the conversion process.  Allows
             preprocessors to pass variables into the Jinja engine.
         """
         
         resources['inlining'] = {}
         resources['inlining']['css'] = self.header
         
         return nb, resources
 
 
     def _regen_header(self):
         """ 
         Fills self.header with lines of CSS extracted from IPython 
         and Pygments.
         """
         from pygments.formatters import HtmlFormatter
         
         #Clear existing header.
         header = []
         
         #Construct path to IPy CSS
-        sheet_filename = os.path.join(path.get_ipython_package_dir(), 
-            'html', 'static', 'style', 'style.min.css')
+        from IPython.html import DEFAULT_STATIC_FILES_PATH
+        sheet_filename = os.path.join(DEFAULT_STATIC_FILES_PATH,
+            'style', 'style.min.css')
         
         #Load style CSS file.
         with io.open(sheet_filename, encoding='utf-8') as file:
             file_text = file.read()
             header.append(file_text)
 
         #Add pygments CSS
         formatter = HtmlFormatter()
         pygments_css = formatter.get_style_defs(self.highlight_class)
         header.append(pygments_css)
 
         #Set header        
         self.header = header