Reserve Vector's capacity manually in CachedMetadata

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/AnimationEffectReadOnly.idl',
             'animation/AnimationEffectTiming.idl',
@@ skipping 1666 matching lines @@
             'editing/state_machines/BackwardGraphemeBoundaryStateMachine.h',
             'editing/state_machines/ForwardGraphemeBoundaryStateMachine.cpp',
             'editing/state_machines/ForwardGraphemeBoundaryStateMachine.h',
             'editing/state_machines/TextSegmentationMachineState.cpp',
             'editing/state_machines/TextSegmentationMachineState.h',
             'editing/state_machines/StateMachineUtil.cpp',
             'editing/state_machines/StateMachineUtil.h',
             'fetch/AccessControlStatus.h',
             'fetch/CSSStyleSheetResource.cpp',
             'fetch/CSSStyleSheetResource.h',
+            'fetch/CachedMetadata.cpp',
             'fetch/CachedMetadata.h',
             'fetch/CachedMetadataHandler.h',
             'fetch/ClientHintsPreferences.cpp',
             'fetch/ClientHintsPreferences.h',
             'fetch/CrossOriginAccessControl.cpp',
             'fetch/CrossOriginAccessControl.h',
             'fetch/DocumentResource.cpp',
             'fetch/DocumentResource.h',
             'fetch/DocumentResourceReference.h',
             'fetch/FetchContext.cpp',
@@ skipping 2601 matching lines @@
             'timing/MemoryInfoTest.cpp',
             'timing/PerformanceBaseTest.cpp',
             'timing/PerformanceObserverTest.cpp',
             'workers/DedicatedWorkerTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }