Remove WebURLRequest::initialize() and simplify WebURLRequest

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 358 matching lines @@
       'exported/WebStorageQuotaCallbacks.cpp',
       'exported/WebTextRun.cpp',
       'exported/WebThreadSafeData.cpp',
       'exported/WebTraceLocation.cpp',
       'exported/WebURL.cpp',
       'exported/WebURLError.cpp',
       'exported/WebURLLoaderClient.cpp',
       'exported/WebURLLoaderTestDelegate.cpp',
       'exported/WebURLLoadTiming.cpp',
       'exported/WebURLRequest.cpp',
-      'exported/WebURLRequestPrivate.h',
       'exported/WebURLResponse.cpp',
       'exported/WrappedResourceRequest.h',
       'exported/WrappedResourceResponse.h',
       'fonts/AcceptLanguagesResolver.cpp',
       'fonts/AcceptLanguagesResolver.h',
       'fonts/AlternateFontFamily.h',
       'fonts/CharacterRange.h',
       'fonts/CustomFontData.h',
       'fonts/Font.cpp',
       'fonts/Font.h',
@@ skipping 959 matching lines @@
       ['use_default_render_theme==1',
         {
           'platform_test_files': [
             'scroll/ScrollbarThemeAuraTest.cpp',
           ],
         }
       ],
     ],
   },
 }