Revert r189385 "Remove LifecycleContext" and r189391, r189530, r189456 that block it

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 40 matching lines @@
       'LayoutTestSupport.h',
       'LayoutUnit.h',
       'Length.cpp',
       'Length.h',
       'LengthBox.cpp',
       'LengthBox.h',
       'LengthFunctions.cpp',
       'LengthFunctions.h',
       'LengthPoint.h',
       'LengthSize.h',
+      'LifecycleContext.h',
       'LifecycleNotifier.h',
       'LifecycleObserver.h',
       'LinkHash.cpp',
       'LinkHash.h',
       'Logging.cpp',
       'Logging.h',
       'MIMETypeFromURL.cpp',
       'MIMETypeFromURL.h',
       'MIMETypeRegistry.cpp',
       'MIMETypeRegistry.h',
@@ skipping 916 matching lines @@
       'graphics/ImageLayerChromiumTest.cpp',
       'graphics/test/MockImageDecoder.h',
       'graphics/test/MockWebGraphicsContext3D.h',
       'image-decoders/bmp/BMPImageDecoderTest.cpp',
       'image-decoders/gif/GIFImageDecoderTest.cpp',
       'image-decoders/jpeg/JPEGImageDecoderTest.cpp',
       'image-decoders/webp/WEBPImageDecoderTest.cpp',
     ],
   },
 }