Vibration API: use runtime flag, change from client to platform.

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': [],
 
@@ skipping 102 matching lines @@
       'speech/SpeechRecognition.idl',
       'speech/SpeechRecognitionAlternative.idl',
       'speech/SpeechRecognitionError.idl',
       'speech/SpeechRecognitionEvent.idl',
       'speech/SpeechRecognitionResult.idl',
       'speech/SpeechRecognitionResultList.idl',
       'speech/SpeechSynthesis.idl',
       'speech/SpeechSynthesisEvent.idl',
       'speech/SpeechSynthesisUtterance.idl',
       'speech/SpeechSynthesisVoice.idl',
+      'vibration/NavigatorVibration.idl',
       'webaudio/AudioBuffer.idl',
       'webaudio/AudioBufferCallback.idl',
       'webaudio/AudioBufferSourceNode.idl',
       'webaudio/ChannelMergerNode.idl',
       'webaudio/ChannelSplitterNode.idl',
       'webaudio/AudioContext.idl',
       'webaudio/AudioDestinationNode.idl',
       'webaudio/GainNode.idl',
       'webaudio/AudioListener.idl',
       'webaudio/AudioNode.idl',
@@ skipping 312 matching lines @@
       'speech/SpeechRecognitionResultList.cpp',
       'speech/SpeechRecognitionResultList.h',
       'speech/SpeechSynthesis.cpp',
       'speech/SpeechSynthesis.h',
       'speech/SpeechSynthesisEvent.cpp',
       'speech/SpeechSynthesisEvent.h',
       'speech/SpeechSynthesisUtterance.cpp',
       'speech/SpeechSynthesisUtterance.h',
       'speech/SpeechSynthesisVoice.cpp',
       'speech/SpeechSynthesisVoice.h',
+      'vibration/NavigatorVibration.cpp',
+      'vibration/NavigatorVibration.h',
       'webaudio/AudioBasicInspectorNode.cpp',
       'webaudio/AudioBasicInspectorNode.h',
       'webaudio/AudioBasicProcessorNode.cpp',
       'webaudio/AudioBasicProcessorNode.h',
       'webaudio/AudioBuffer.cpp',
       'webaudio/AudioBuffer.h',
       'webaudio/AudioBufferCallback.h',
       'webaudio/AudioBufferSourceNode.cpp',
       'webaudio/AudioBufferSourceNode.h',
       'webaudio/ChannelMergerNode.cpp',
@@ skipping 194 matching lines @@
       'websockets/WorkerThreadableWebSocketChannel.cpp',
       'websockets/WorkerThreadableWebSocketChannel.h',
     ],
     'modules_unittest_files': [
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }