Add blink::ServiceRegistry and expose it from LocalFrame and Platform.

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 271 matching lines @@
       'clipboard/ClipboardUtilities.h',
       'clipboard/ClipboardUtilitiesPosix.cpp',
       'clipboard/ClipboardUtilitiesWin.cpp',
       'credentialmanager/PlatformCredential.cpp',
       'credentialmanager/PlatformCredential.h',
       'credentialmanager/PlatformFederatedCredential.cpp',
       'credentialmanager/PlatformFederatedCredential.h',
       'credentialmanager/PlatformPasswordCredential.cpp',
       'credentialmanager/PlatformPasswordCredential.h',
       'exported/Platform.cpp',
+      'exported/ServiceRegistry.cpp',
       'exported/WebActiveGestureAnimation.cpp',
       'exported/WebActiveGestureAnimation.h',
       'exported/WebAudioBus.cpp',
       'exported/WebAudioDevice.cpp',
       'exported/WebBlobData.cpp',
       'exported/WebCanvasCaptureHandler.cpp',
       'exported/WebContentDecryptionModule.cpp',
       'exported/WebContentDecryptionModuleAccess.cpp',
       'exported/WebContentDecryptionModuleResult.cpp',
       'exported/WebContentDecryptionModuleSession.cpp',
@@ skipping 991 matching lines @@
       ['OS!="mac"',
         {
           'platform_test_files': [
             'scroll/ScrollAnimatorTest.cpp',
           ],
         }
       ],
     ],
   },
 }