Fix an edge case where early disconnect() can omit delivering of observation. crbug/607324

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 4103 matching lines @@
             'streams/ReadableStreamOperationsTest.cpp',
             'streams/ReadableStreamReaderTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
+            'timing/PerformanceBaseTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }