Refactor the API for setting dynamic resource load priorities

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1447 matching lines @@
             'fetch/LinkFetchResource.h',
             'fetch/MemoryCache.cpp',
             'fetch/MemoryCache.h',
             'fetch/RawResource.cpp',
             'fetch/RawResource.h',
             'fetch/Resource.cpp',
             'fetch/Resource.h',
             'fetch/ResourceClientWalker.h',
             'fetch/ResourceFetcher.cpp',
             'fetch/ResourceFetcher.h',
-            'fetch/ResourceLoadPriorityOptimizer.cpp',
-            'fetch/ResourceLoadPriorityOptimizer.h',
             'fetch/ResourceLoader.cpp',
             'fetch/ResourceLoader.h',
             'fetch/ResourceLoaderOptions.h',
             'fetch/ResourceLoaderSet.cpp',
             'fetch/ResourceLoaderSet.h',
             'fetch/ResourcePtr.cpp',
             'fetch/ResourcePtr.h',
             'fetch/ScriptResource.cpp',
             'fetch/ScriptResource.h',
             'fetch/SubstituteData.h',
@@ skipping 2380 matching lines @@
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }