[webcrypto] Add the KeyAlgorithm interface.

Source/modules/modules.gypi

 {
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
     # ways.
     'extra_blink_module_idl_files': [],
     'extra_blink_module_files': [],
     # Files for which bindings (.cpp and .h files) will be generated
     'modules_idl_files': [
       '<@(extra_blink_module_idl_files)',
-      'crypto/Algorithm.idl',
+      'crypto/AesKeyAlgorithm.idl',
       'crypto/Crypto.idl',
+      'crypto/HmacKeyAlgorithm.idl',
       'crypto/Key.idl',
+      'crypto/KeyAlgorithm.idl',
       'crypto/KeyPair.idl',
+      'crypto/RsaHashedKeyAlgorithm.idl',
+      'crypto/RsaKeyAlgorithm.idl',
       'crypto/SubtleCrypto.idl',
       'crypto/WorkerCrypto.idl',
       'device_orientation/DeviceAcceleration.idl',
       'device_orientation/DeviceMotionEvent.idl',
       'device_orientation/DeviceOrientationEvent.idl',
       'device_orientation/DeviceRotationRate.idl',
       'encoding/TextDecoder.idl',
       'encoding/TextEncoder.idl',
       'encryptedmedia/MediaKeyMessageEvent.idl',
       'encryptedmedia/MediaKeyNeededEvent.idl',
@@ skipping 181 matching lines @@
       'screen_orientation/ScreenOrientation.idl',
       'serviceworkers/NavigatorServiceWorker.idl',
       'speech/WindowSpeechSynthesis.idl',
       'vibration/NavigatorVibration.idl',
       'webdatabase/WindowWebDatabase.idl',
       'webdatabase/WorkerGlobalScopeWebDatabase.idl',
       'webmidi/NavigatorWebMIDI.idl',
     ],
     'modules_files': [
       '<@(extra_blink_module_files)',
-      'crypto/Algorithm.cpp',
-      'crypto/Algorithm.h',
       'crypto/Crypto.cpp',
       'crypto/Crypto.h',
       'crypto/CryptoResultImpl.cpp',
       'crypto/CryptoResultImpl.h',
       'crypto/DOMWindowCrypto.cpp',
       'crypto/DOMWindowCrypto.h',
       'crypto/Key.cpp',
+      'crypto/AesKeyAlgorithm.cpp',
+      'crypto/AesKeyAlgorithm.h',
+      'crypto/HmacKeyAlgorithm.cpp',
+      'crypto/HmacKeyAlgorithm.h',
       'crypto/Key.h',
+      'crypto/KeyAlgorithm.cpp',
+      'crypto/KeyAlgorithm.h',
+      'crypto/RsaHashedKeyAlgorithm.cpp',
+      'crypto/RsaHashedKeyAlgorithm.h',
+      'crypto/RsaKeyAlgorithm.cpp',
+      'crypto/RsaKeyAlgorithm.h',
       'crypto/KeyPair.cpp',
       'crypto/KeyPair.h',
       'crypto/NormalizeAlgorithm.cpp',
       'crypto/NormalizeAlgorithm.h',
       'crypto/SubtleCrypto.cpp',
       'crypto/SubtleCrypto.h',
       'crypto/WorkerCrypto.cpp',
       'crypto/WorkerCrypto.h',
       'crypto/WorkerGlobalScopeCrypto.cpp',
       'crypto/WorkerGlobalScopeCrypto.h',
@@ skipping 606 matching lines @@
       'indexeddb/IDBKeyPathTest.cpp',
       'indexeddb/IDBRequestTest.cpp',
       'indexeddb/IDBTransactionTest.cpp',
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketExtensionParserTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }