Docserver: Attach intro metadata to the template itself, not to an object which

chrome/common/extensions/docs/server2/template_renderer.py

 # Copyright 2013 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.
 
 import logging
 
 from data_source_registry import CreateDataSources
 from third_party.handlebar import Handlebar
 from url_constants import GITHUB_BASE, EXTENSIONS_SAMPLES
 
 
 class TemplateRenderer(object):
   '''Renders templates with the server's available data sources.
   '''
 
   def __init__(self, server_instance):
     self._server_instance = server_instance
 
-  def Render(self, template, request):
+  def Render(self, template, request, data_sources=None, warn=True):
+    '''Renders |template| using |request|.
+    Specify |data_sources| to only include the DataSources with the given names
+    when rendering the template.
+    Specify |warn| whether to warn (e.g. logging.warning) if there are template
+    rendering errors. It may be useful to disable this when errors are expected,
+    for example when doing an initial page render to determine document title.
+    '''
     assert isinstance(template, Handlebar), type(template)
-    server_instance = self._server_instance
-    render_context = {
-      'api_list': server_instance.api_list_data_source_factory.Create(),
-      'apis': server_instance.api_data_source_factory.Create(request),
+    render_context = self._CreateDataSources(request)
+    if data_sources is not None:
+      render_context = dict((name, d) for name, d in render_context.iteritems()
+                            if name in data_sources)
+    render_context.update({
       'apps_samples_url': GITHUB_BASE,
-      'base_path': server_instance.base_path,
+      'base_path': self._server_instance.base_path,
       'extensions_samples_url': EXTENSIONS_SAMPLES,
-      'samples': server_instance.samples_data_source_factory.Create(request),
-      'static': server_instance.base_path + 'static',
-    }
-    render_context.update(CreateDataSources(server_instance, request=request))
-    render_data = template.render(render_context)
-    if render_data.errors:
+      'static': self._server_instance.base_path + 'static',
+    })
+    render_data = template.Render(render_context)
+    if warn and render_data.errors:
       logging.error('Handlebar error(s) rendering %s:\n%s' %
           (template._name, '  \n'.join(render_data.errors)))
     return render_data.text
+
+  def _CreateDataSources(self, request):
+    server_instance = self._server_instance
+    data_sources = CreateDataSources(server_instance, request=request)
+    data_sources.update({
+      'api_list': server_instance.api_list_data_source_factory.Create(),
+      'apis': server_instance.api_data_source_factory.Create(request),
+      'samples': server_instance.samples_data_source_factory.Create(request),
+    })
+    return data_sources