Add API Key parsing for experimental APIs

third_party/WebKit/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 1472 matching lines @@
             'editing/serializers/StyledMarkupSerializer.cpp',
             'editing/serializers/StyledMarkupSerializer.h',
             'editing/serializers/TextOffset.cpp',
             'editing/serializers/TextOffset.h',
             'editing/spellcheck/SpellCheckRequester.cpp',
             'editing/spellcheck/SpellCheckRequester.h',
             'editing/spellcheck/SpellChecker.cpp',
             'editing/spellcheck/SpellChecker.h',
             'editing/spellcheck/TextCheckingHelper.cpp',
             'editing/spellcheck/TextCheckingHelper.h',
+            'experiments/APIKey.cpp',
+            'experiments/APIKey.h',
             'experiments/Experiments.cpp',
             'experiments/Experiments.h',
             'fetch/AccessControlStatus.h',
             'fetch/CSSStyleSheetResource.cpp',
             'fetch/CSSStyleSheetResource.h',
             'fetch/CachedMetadata.h',
             'fetch/CachedMetadataHandler.h',
             'fetch/ClientHintsPreferences.cpp',
             'fetch/ClientHintsPreferences.h',
             'fetch/CrossOriginAccessControl.cpp',
@@ skipping 2363 matching lines @@
             'editing/iterators/TextIteratorTest.cpp',
             'editing/markers/DocumentMarkerControllerTest.cpp',
             'editing/PositionTest.cpp',
             'editing/SurroundingTextTest.cpp',
             'editing/VisiblePositionTest.cpp',
             'editing/VisibleSelectionTest.cpp',
             'editing/VisibleUnitsTest.cpp',
             'editing/serializers/StyledMarkupSerializerTest.cpp',
             'events/EventPathTest.cpp',
             'events/PointerEventFactoryTest.cpp',
+            'experiments/APIKeyTest.cpp',
             'experiments/ExperimentsTest.cpp',
             'fetch/CachingCorrectnessTest.cpp',
             'fetch/ClientHintsPreferencesTest.cpp',
             'fetch/FetchUtilsTest.cpp',
             'fetch/ImageResourceTest.cpp',
             'fetch/MemoryCacheTest.cpp',
             'fetch/MockImageResourceClient.cpp',
             'fetch/RawResourceTest.cpp',
             'fetch/ResourceFetcherTest.cpp',
             'fetch/ResourceLoaderOptionsTest.cpp',
@@ skipping 81 matching lines @@
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }