Revert "Remove SkPDFDocument and SkPDFDevice from the public headers."

gyp/tools.gyp

     # GYP file to build various tools.
 #
 # To build on Linux:
 #  ./gyp_skia tools.gyp && make tools
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
@@ skipping 616 matching lines @@
       'variables': {
         'includes_to_test': [
           '<(skia_include_path)/animator',
           '<(skia_include_path)/c',
           '<(skia_include_path)/config',
           '<(skia_include_path)/core',
           '<(skia_include_path)/effects',
           '<(skia_include_path)/gpu',
           '<(skia_include_path)/images',
           '<(skia_include_path)/pathops',
+          '<(skia_include_path)/pdf',
           '<(skia_include_path)/pipe',
           '<(skia_include_path)/ports',
           '<(skia_include_path)/svg',
           '<(skia_include_path)/utils',
           '<(skia_include_path)/views',
           '<(skia_include_path)/xml',
         ],
         'paths_to_ignore': [
           '<(skia_include_path)/gpu/gl/GrGLConfig_chrome.h',
           '<(skia_include_path)/ports/SkTypeface_mac.h',
@@ skipping 124 matching lines @@
               'flags.gyp:flags',
               'skia_lib.gyp:skia_lib',
               'resources',
             ],
           },
         ],
       },
     ],
   ],
 }