blinkbuild: Remove external usage of upper_first_letter().

NameStyleConverter.to_function_name() works well for
make_media_features.py. Also, rename the filter from
'upper_first_letter' to 'to_function_name'.

Makes upper_first_letter() private.

Bug: 843927
Change-Id: Id3cedbbc66f01c839d2ef2a4294073aae5896222
Reviewed-on: https://chromium-review.googlesource.com/1080109Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563102}

third_party/blink/renderer/build/scripts/core/css/make_media_features.py

@@ -8,10 +8,10 @@ import os
 import sys
 sys.path.append(os.path.join(os.path.dirname(__file__), '../..'))
 
+from blinkbuild.name_style_converter import NameStyleConverter
 import media_feature_symbol
 import json5_generator
 import template_expander
-import name_utilities
 
 
 class MakeMediaFeaturesWriter(json5_generator.Writer):
@@ -21,7 +21,7 @@ class MakeMediaFeaturesWriter(json5_generator.Writer):
     }
     filters = {
         'symbol': media_feature_symbol.getMediaFeatureSymbolWithSuffix(''),
-        'upper_first_letter': name_utilities.upper_first_letter,
+        'to_function_name': lambda symbol: NameStyleConverter(symbol).to_function_name(),
     }
 
     def __init__(self, json5_file_path, output_dir):

third_party/blink/renderer/build/scripts/core/css/templates/media_features.h.tmpl

@@ -9,7 +9,7 @@
 #define CSS_MEDIAQUERY_NAMES_FOR_EACH_MEDIAFEATURE(macro) \
     {% for entry in entries %}
     {% set constant_prefix = entry | symbol %}
-    {% set method_prefix = constant_prefix | upper_first_letter %}
+    {% set method_prefix = constant_prefix | to_function_name %}
     macro({{constant_prefix}}, {{method_prefix}}){% if not loop.last %} \
     {% endif %}
     {% endfor %}

third_party/blink/renderer/build/scripts/name_utilities.py

@@ -32,7 +32,7 @@ import re
 from blinkbuild.name_style_converter import NameStyleConverter, tokenize_name
 
 
-def upper_first_letter(name):
+def _upper_first_letter(name):
     """Return name with first letter uppercased."""
     if not name:
         return ''
@@ -94,7 +94,7 @@ def naming_style(f):
 
 @naming_style
 def _upper_camel_case(words):
-    return ''.join(upper_first_letter(word) for word in words)
+    return ''.join(_upper_first_letter(word) for word in words)
 
 
 @naming_style