UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3278.0 Safari/537.36

Example URL:
chrome://flags/#network-service

Steps to reproduce the problem:
1. Enable «Enable network service» chrome://flags/#network-service
2. Restart Chrome
3. Try to open any PDF (local or remote)

What is the expected behavior?
Chrome will display PDF content.

What went wrong?
Chrome just downloads PDF instead of opening.

Did this work before? N/A 

Chrome version: 64.0.3278.0  Channel: dev
OS Version: 10.0
Flash Version: 

Google Chrome	64.0.3278.0 (Official Build) dev (64-bit) (cohort: Dev)
Revision	6218872807f9d8f9e64630c7cefe0ab18954585a-refs/heads/master@{#519169}
OS	Windows
JavaScript	V8 6.4.370
Flash	28.0.0.120 C:\Users\User\AppData\Local\Google\Chrome Dev\User Data\PepperFlash\28.0.0.120\pepflashplayer.dll
User Agent	Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3278.0 Safari/537.36
Command Line	"C:\Program Files (x86)\Google\Chrome Dev\Application\chrome.exe" --flag-switches-begin --enable-browser-task-scheduler --enable-checker-imaging --enable-devtools-experiments --enable-experimental-canvas-features --enable-experimental-web-platform-features --enable-gpu-rasterization --enable-input-ime-api --javascript-harmony --enabled-new-style-notification --enable-offline-auto-reload-visible-only --enable-offline-auto-reload --enable-picture-in-picture --enable-quic --enable-scroll-prediction --use-simple-cache-backend=on --site-per-process --enable-site-settings --enable-spelling-feedback-field-trial --enable-tab-audio-muting --enable-webgl-draft-extensions --enable-zero-copy --gpu-rasterization-msaa-sample-count=16 --ignore-gpu-blacklist --enable-lcd-text --num-raster-threads=4 --enable-smooth-scrolling --v8-cache-options=code --enable-features=AnimatedAppMenuIcon,AsmJsToWebAssembly,AutomaticTabDiscarding,CaptureThumbnailOnNavigatingAway,D3DVsync,EnableUsernameCorrection,ExpensiveBackgroundTimerThrottling,FontCacheScaling,LoadingWithMojo,MaterialDesignBookmarks,MaterialDesignExtensions,MaterialDesignIncognitoNTP,MemoryCoordinator,ModuleScriptsDynamicImport,MojoVideoEncodeAccelerator,NavigationMojoResponse,NewPrintPreview,NoStatePrefetch,OffMainThreadFetch,OmniboxEntitySuggestions,OmniboxSpeculativeServiceWorkerStartOnQueryInput,OmniboxTabSwitchSuggestions,OmniboxTailSuggestions,OmniboxUIExperimentElideSuggestionUrlAfterHost,OmniboxUIExperimentShowSuggestionFavicons,OneGoogleBarOnLocalNtp,OutOfBlinkCORS,OverlayScrollbar,OverlayScrollbarFlashAfterAnyScrollUpdate,OverlayScrollbarFlashWhenMouseEnter,PWAFullCodeCache,ParallelDownloading,PauseBackgroundTabs,PolicyTool,ResourceLoadScheduler,SecondaryUiMd,ServiceWorkerScriptFullCodeCache,ServiceWorkerScriptStreaming,SoundContentSetting,SpeculativeResourcePrefetching,TabsInCBD,TranslateRankerEnforcement,TranslateUI2016Q2,UseGoogleLocalNtp,V8VmFuture,WebAssembly,WebAssemblyStreaming,brotli-encoding,browser-side-navigation,top-document-isolation --flag-switches-end