WebCrypto: Add WebKit API structure for keys.

Source/core/core.gypi

 {
     'variables': {
         'core_idl_files': [
             'css/CSS.idl',
             'css/CSSCharsetRule.idl',
             'css/CSSFontFaceLoadEvent.idl',
             'css/CSSFontFaceRule.idl',
             'css/CSSHostRule.idl',
             'css/CSSImportRule.idl',
             'css/CSSMediaRule.idl',
@@ skipping 3614 matching lines @@
             'testing/TypeConversions.h',
             '<(SHARED_INTERMEDIATE_DIR)/webkit/InternalSettingsGenerated.cpp',
             '<(SHARED_INTERMEDIATE_DIR)/webkit/InternalSettingsGenerated.h',
         ],
         'webcore_platform_support_files': [
             'platform/chromium/support/Platform.cpp',
             'platform/chromium/support/WebActiveGestureAnimation.cpp',
             'platform/chromium/support/WebActiveGestureAnimation.h',
             'platform/chromium/support/WebAudioBus.cpp',
             'platform/chromium/support/WebCryptoAlgorithm.cpp',
+            'platform/chromium/support/WebCryptoKey.cpp',
             'platform/chromium/support/WebCursorInfo.cpp',
             'platform/chromium/support/WebData.cpp',
             'platform/chromium/support/WebDeviceMotionData.cpp',
             'platform/chromium/support/WebFloatQuad.cpp',
             'platform/chromium/support/WebHTTPBody.cpp',
             'platform/chromium/support/WebHTTPLoadInfo.cpp',
             'platform/chromium/support/WebMediaConstraints.cpp',
             'platform/chromium/support/WebMediaStream.cpp',
             'platform/chromium/support/WebMediaStreamSource.cpp',
             'platform/chromium/support/WebMediaStreamTrack.cpp',
@@ skipping 81 matching lines @@
                 'bison_exe': 'bison',
                 # We specify a preprocess so it happens locally and won't get
                 # distributed to goma.
                 # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
                 # use /usr/bin/clang once we require Xcode 4.x.
                 'preprocessor': '--preprocessor "/usr/bin/gcc -E -P -x c++"'
               }],
          ],
     }
 }