Encoding API: ignore leading/trailing whitespace in labels

Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.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
@@ skipping 638 matching lines @@
       'device_orientation/DeviceOrientationDispatcher.cpp',
       'device_orientation/DeviceOrientationDispatcher.h',
       'device_orientation/DeviceOrientationEvent.cpp',
       'device_orientation/DeviceOrientationEvent.h',
       'device_orientation/DeviceOrientationInspectorAgent.cpp',
       'device_orientation/DeviceOrientationInspectorAgent.h',
       'device_orientation/DeviceRotationRate.cpp',
       'device_orientation/DeviceRotationRate.h',
       'donottrack/NavigatorDoNotTrack.cpp',
       'donottrack/NavigatorDoNotTrack.h',
+      'encoding/Encoding.cpp',
+      'encoding/Encoding.h',
       'encoding/TextDecoder.cpp',
       'encoding/TextDecoder.h',
       'encoding/TextEncoder.cpp',
       'encoding/TextEncoder.h',
       'encryptedmedia/ContentDecryptionModuleResultPromise.cpp',
       'encryptedmedia/ContentDecryptionModuleResultPromise.h',
       'encryptedmedia/EncryptedMediaUtils.cpp',
       'encryptedmedia/EncryptedMediaUtils.h',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.cpp',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.h',
@@ skipping 734 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }