Remove non-existing headers from the build

third_party/WebKit/public/BUILD.gn

Index: third_party/WebKit/public/BUILD.gn
diff --git a/third_party/WebKit/public/BUILD.gn b/third_party/WebKit/public/BUILD.gn
index 9f5d938ec5788f67f57f3b5256ff886bf17e772d..ca750bb3d4f157e6f50918d8d80e5a304c03f1df 100644
--- a/third_party/WebKit/public/BUILD.gn
+++ b/third_party/WebKit/public/BUILD.gn
@@ -100,7 +100,6 @@ source_set("blink_headers") {
     "platform/URLConversion.h",
     "platform/UserMetricsAction.h",
     "platform/WebAddressSpace.h",
-    "platform/WebApiKeyValidator.h",
     "platform/WebApplicationCacheHost.h",
     "platform/WebApplicationCacheHostClient.h",
     "platform/WebAudioBus.h",
@@ -235,7 +234,6 @@ source_set("blink_headers") {
     "platform/WebMediaStreamCenterClient.h",
     "platform/WebMediaStreamSource.h",
     "platform/WebMediaStreamTrack.h",
-    "platform/WebMediaStreamTrackSourcesRequest.h",
     "platform/WebMemoryCoordinator.h",
     "platform/WebMemoryPressureLevel.h",
     "platform/WebMemoryState.h",
@@ -260,7 +258,6 @@ source_set("blink_headers") {
     "platform/WebPrerender.h",
     "platform/WebPrerenderingSupport.h",
     "platform/WebPrescientNetworking.h",
-    "platform/WebPrivateOwnPtr.h",
     "platform/WebPrivatePtr.h",
     "platform/WebPublicSuffixList.h",
     "platform/WebRTCAnswerOptions.h",
@@ -290,7 +287,6 @@ source_set("blink_headers") {
     "platform/WebRect.h",
     "platform/WebReferrerPolicy.h",
     "platform/WebRenderingStats.h",
-    "platform/WebScheduler.h",
     "platform/WebScreenInfo.h",
     "platform/WebScrollbar.h",
     "platform/WebScrollbarBehavior.h",
@@ -324,7 +320,6 @@ source_set("blink_headers") {
     "platform/WebThread.h",
     "platform/WebThreadSafeData.h",
     "platform/WebTimeRange.h",
-    "platform/WebTopControlsState.h",
     "platform/WebTouchEvent.h",
     "platform/WebTouchPoint.h",
     "platform/WebTraceLocation.h",
@@ -339,10 +334,8 @@ source_set("blink_headers") {
     "platform/WebURLRequest.h",
     "platform/WebURLResponse.h",
     "platform/WebVector.h",
-    "platform/WebViewScheduler.h",
     "platform/WebViewportStyle.h",
     "platform/WebWorkerFetchContext.h",
-    "platform/callback/WebClosure.h",
     "platform/linux/WebFallbackFont.h",
     "platform/linux/WebFontRenderStyle.h",
     "platform/linux/WebSandboxSupport.h",
@@ -369,7 +362,6 @@ source_set("blink_headers") {
     "platform/modules/media_capabilities/WebAudioConfiguration.h",
     "platform/modules/media_capabilities/WebMediaCapabilitiesClient.h",
     "platform/modules/media_capabilities/WebMediaConfiguration.h",
-    "platform/modules/media_capabilities/WebMediaDecodingAbility.h",
     "platform/modules/media_capabilities/WebVideoConfiguration.h",
     "platform/modules/notifications/WebNotificationAction.h",
     "platform/modules/notifications/WebNotificationConstants.h",
@@ -431,27 +423,16 @@ source_set("blink_headers") {
     "platform/modules/serviceworker/WebServiceWorkerSkipWaitingCallbacks.h",
     "platform/modules/serviceworker/WebServiceWorkerState.h",
     "platform/modules/serviceworker/WebServiceWorkerStreamHandle.h",
-    "platform/modules/vr/WebVR.h",
     "platform/modules/webmidi/WebMIDIAccessor.h",
     "platform/modules/webmidi/WebMIDIAccessorClient.h",
-    "platform/modules/websockets/WebSocketHandle.h",
-    "platform/modules/websockets/WebSocketHandleClient.h",
-    "platform/modules/websockets/WebSocketHandshakeRequestInfo.h",
-    "platform/modules/websockets/WebSocketHandshakeResponseInfo.h",
-    "platform/scheduler/base/task_queue.h",
-    "platform/scheduler/base/task_time_observer.h",
     "platform/scheduler/child/child_scheduler.h",
-    "platform/scheduler/child/compositor_worker_scheduler.h",
     "platform/scheduler/child/single_thread_idle_task_runner.h",
     "platform/scheduler/child/webthread_base.h",
-    "platform/scheduler/child/webthread_impl_for_worker_scheduler.h",
-    "platform/scheduler/child/worker_scheduler.h",
     "platform/scheduler/renderer/render_widget_scheduling_state.h",
     "platform/scheduler/renderer/renderer_scheduler.h",
     "platform/scheduler/test/fake_renderer_scheduler.h",
     "platform/scheduler/test/mock_renderer_scheduler.h",
     "platform/scheduler/test/renderer_scheduler_test_support.h",
-    "platform/scheduler/utility/webthread_impl_for_utility_thread.h",
     "web/WebAXEnums.h",
     "web/WebAXObject.h",
     "web/WebActiveWheelFlingParameters.h",
@@ -470,7 +451,6 @@ source_set("blink_headers") {
     "web/WebColorSuggestion.h",
     "web/WebCompositionUnderline.h",
     "web/WebConsoleMessage.h",
-    "web/WebContentSecurityPolicy.h",
     "web/WebContextMenuData.h",
     "web/WebCryptoNormalize.h",
     "web/WebCustomElement.h",
@@ -584,7 +564,6 @@ source_set("blink_headers") {
     "web/WebSharedWorkerCreationContextType.h",
     "web/WebSharedWorkerCreationErrors.h",
     "web/WebSharedWorkerRepositoryClient.h",
-    "web/WebSourceLocation.h",
     "web/WebSpeechGrammar.h",
     "web/WebSpeechRecognitionHandle.h",
     "web/WebSpeechRecognitionParams.h",