osr: Implement shared texture support (fixes #1006, fixes #2575)

Adds support for the OnAcceleratedPaint callback. Verified to work
on macOS and Windows. Linux support is present but not implemented
for cefclient, so it is not verified to work.

To test:
Run `cefclient --off-screen-rendering-enabled --shared-texture-enabled`

tools/cef_parser.py

@@ -24,13 +24,16 @@ def wrap_text(text, indent='', maxchars=80, listitem=False):
     necessary a line will be broken and wrapped after a word.
     """
   if listitem:
-    initial_indent=indent + '- '
-    subsequent_indent=indent+'  '
+    initial_indent = indent + '- '
+    subsequent_indent = indent + '  '
   else:
-    initial_indent=indent
-    subsequent_indent=indent
-  lines = textwrap.wrap(text, maxchars, initial_indent=initial_indent,
-                        subsequent_indent=subsequent_indent)
+    initial_indent = indent
+    subsequent_indent = indent
+  lines = textwrap.wrap(
+      text,
+      maxchars,
+      initial_indent=initial_indent,
+      subsequent_indent=subsequent_indent)
   return '\n'.join(lines) + '\n'
 
 
@@ -187,7 +190,7 @@ def format_comment(comment, indent, translate_map=None, maxchars=80):
           else:
             result += line
         result += '\n'
-        listitem = False;
+        listitem = False
       else:
         if not listitem:
           # add to the current paragraph
@@ -395,6 +398,9 @@ _simpletypes = {
     'char* const': ['char* const', 'NULL'],
     'cef_color_t': ['cef_color_t', '0'],
     'cef_json_parser_error_t': ['cef_json_parser_error_t', 'JSON_NO_ERROR'],
+    'CefAcceleratedPaintInfo': [
+        'cef_accelerated_paint_info_t', 'CefAcceleratedPaintInfo()'
+    ],
     'CefAudioParameters': ['cef_audio_parameters_t', 'CefAudioParameters()'],
     'CefBaseTime': ['cef_basetime_t', 'CefBaseTime()'],
     'CefBoxLayoutSettings': [