This failure seems to be occurring only on Android and only when the Network Service is enabled however a missing pak file shouldn't be related to enabling the Network Service. The failure is flaky.

[ RUN      ] RenderThreadImplBrowserTest.NonResourceDispatchIPCTasksDontGoThroughScheduler
[ERROR:resource_bundle_android.cc(52)] Failed to open pak file: assets/chrome_100_percent.pak
[WARNING:resource_bundle_android.cc(124)] locale_file_path.empty() for locale
[FATAL:child_process_launcher_helper_android.cc(120)] Check failed: 0 <= fd. : Success (0)
[ERROR:test_suite.cc(301)] Currently running: RenderThreadImplBrowserTest.NonResourceDispatchIPCTasksDontGoThroughScheduler
Searching for native crashes in: /b/swarming/w/it_NRFvA/tmpgqVdzE
Unknown Android release, consider passing --packed-lib.
Reading Android symbols from: /b/swarming/w/ir
Searching for Chrome symbols from within: /b/swarming/w/ir/out/Release/lib.unstripped:/b/swarming/w/ir/out/Release/lib:/b/swarming/w/ir/out/Release
Stack Trace:
  RELADDR   FUNCTION                                                                                                                                                                                                                                          FILE:LINE
  0000000001edd133  logging::LogMessage::~LogMessage()                                                                                                                                                                                                                ??:0:0
  0000000001edd7fb  logging::ErrnoLogMessage::~ErrnoLogMessage()                                                                                                                                                                                                      ??:0:0
  0000000002bfcf5f  content::internal::ChildProcessLauncherHelper::LaunchProcessOnLauncherThread(base::LaunchOptions const&, std::__ndk1::unique_ptr<content::PosixFileDescriptorInfo, std::__ndk1::default_delete<content::PosixFileDescriptorInfo> >, bool*, int*)  ??:0:0
  0000000002bfc3ff  content::internal::ChildProcessLauncherHelper::LaunchOnLauncherThread()                                                                                                                                                                           ??:0:0
  0000000001ec85bf  base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*)                                                                                                                                                                              ??:0:0
  0000000001ee2bef  base::MessageLoop::RunTask(base::PendingTask*)                                                                                                                                                                                                    ??:0:0
  0000000001ee2fef  base::MessageLoop::DoWork()                                                                                                                                                                                                                       ??:0:0
  0000000001ee3887  Java_org_chromium_base_SystemMessageHandler_nativeDoRunLoopOnce                                                                                                                                                                                   ??:0:0
  0000000000b2c5df  <UNKNOWN>                                                                                                                                                                                                                                         /data/app/org.chromium.content_browsertests_apk-1/oat/arm64/base.odex
  0000000000b2cae3  <UNKNOWN>                                                                                                                                                                                                                                         /data/app/org.chromium.content_browsertests_apk-1/oat/arm64/base.odex
  00000000029d07c7  <UNKNOWN>