Revert "Enable NetworkService by default on ChromeOS"

This reverts commit 56a50dae.

Reason for revert: Suspect causing  browser_tests, viz_browser_tests, non_single_process_mash_browser_tests failures on Linux Chromium OS ASan LSan Tests (1).

E.g.
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Chromium%20OS%20ASan%20LSan%20Tests%20%281%29/31690

https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8920872960619542176/+/steps/browser_tests/0/logs/DownloadNotificationTest.IncognitoDownloadFile__status_CRASH_/0

==19438==ERROR: AddressSanitizer: heap-use-after-free on address 0x60d0001b7a80 at pc 0x55f331c5ce2d bp 0x7f3096281310 sp 0x7f3096281308
READ of size 8 at 0x60d0001b7a80 thread T6 (Chrome_IOThread)
    #0 0x55f331c5ce2c in content::URLLoaderFactoryGetter::SetNetworkFactoryForTesting(network::mojom::URLLoaderFactory*, bool) ./../../content/browser/url_loader_factory_getter.cc:226:5

... 

Original change's description:
> Enable NetworkService by default on ChromeOS
> 
> Bug: 920038
> Change-Id: I577d9d497bc564b885a4a96ce5baf4f3326ce1a8
> Reviewed-on: https://chromium-review.googlesource.com/c/1464069
> Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#634333}

TBR=jam@chromium.org,jbudorick@chromium.org,rmcelrath@chromium.org

Change-Id: Ibfeeadd47f94d4ff4a87ed9518c9bc0d7f2e30b6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 920038
Reviewed-on: https://chromium-review.googlesource.com/c/1482099Reviewed-by: Takashi Sakamoto <tasak@google.com>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#634509}

services/network/public/cpp/features.cc

@@ -15,14 +15,8 @@ const base::Feature kExpectCTReporting{"ExpectCTReporting",
 const base::Feature kNetworkErrorLogging{"NetworkErrorLogging",
                                          base::FEATURE_ENABLED_BY_DEFAULT};
 // Enables the network service.
-const base::Feature kNetworkService {
-  "NetworkService",
-#if defined(OS_CHROMEOS)
-      base::FEATURE_ENABLED_BY_DEFAULT
-#else
-      base::FEATURE_DISABLED_BY_DEFAULT
-#endif
-};
+const base::Feature kNetworkService{"NetworkService",
+                                    base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Out of Blink CORS
 const base::Feature kOutOfBlinkCors{"OutOfBlinkCors",

testing/buildbot/chromium.chromiumos.json

@@ -578,17 +578,6 @@
         },
         "test": "browser_tests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_browser_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "shards": 10
-        },
-        "test": "browser_tests"
-      },
       {
         "args": [
           "--disable-features=SingleProcessMash",
@@ -681,16 +670,6 @@
         },
         "test": "components_browsertests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_components_browsertests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "components_browsertests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ -710,16 +689,6 @@
         },
         "test": "content_browsertests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_content_browsertests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "content_browsertests"
-      },
       {
         "args": [
           "--disable-features=SingleProcessMash",
@@ -832,16 +801,6 @@
         },
         "test": "extensions_browsertests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_extensions_browsertests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "extensions_browsertests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ -897,17 +856,6 @@
         },
         "test": "interactive_ui_tests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_interactive_ui_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "shards": 3
-        },
-        "test": "interactive_ui_tests"
-      },
       {
         "args": [
           "--disable-features=SingleProcessMash"
@@ -1132,16 +1080,6 @@
         },
         "test": "sync_integration_tests"
       },
-      {
-        "args": [
-          "--disable-features=NetworkService"
-        ],
-        "name": "non_network_service_sync_integration_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
-        "test": "sync_integration_tests"
-      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true

testing/buildbot/test_suites.pyl

@@ -4081,51 +4081,6 @@
       'crashpad_tests': {},
     },
 
-    'non_network_service_gtests': {
-      'non_network_service_browser_tests': {
-        'args': [
-          '--disable-features=NetworkService',
-        ],
-        'swarming': {
-          'shards': 10,
-        },
-        'test': 'browser_tests',
-      },
-      'non_network_service_components_browsertests': {
-        'args': [
-          '--disable-features=NetworkService',
-        ],
-        'test': 'components_browsertests',
-      },
-      'non_network_service_content_browsertests': {
-        'args': [
-          '--disable-features=NetworkService',
-        ],
-        'test': 'content_browsertests',
-      },
-      'non_network_service_extensions_browsertests': {
-        'args': [
-          '--disable-features=NetworkService',
-        ],
-        'test': 'extensions_browsertests',
-      },
-      'non_network_service_interactive_ui_tests': {
-        'args': [
-          '--disable-features=NetworkService'
-        ],
-        'swarming': {
-          'shards': 3,
-        },
-        'test': 'interactive_ui_tests',
-      },
-      'non_network_service_sync_integration_tests': {
-        'args': [
-          '--disable-features=NetworkService'
-        ],
-        'test': 'sync_integration_tests',
-      },
-    },
-
     'non_viz_fyi_chromium_gtests': {
       'non_viz_content_browsertests': {
         'args': [
@@ -5015,24 +4970,6 @@
       'viz_gtests',
     ],
 
-    'linux_chromeos_with_non_network_service_gtests': [
-      # This is:
-      #   linux_chromeos_gtests
-      #   + non_newtork_service_gtests
-      'aura_gtests',
-      'chromium_gtests',
-      'chromium_gtests_for_devices_with_graphical_output',
-      'chromium_gtests_for_linux_and_chromeos_only',
-      'chromium_gtests_for_win_and_linux_only',
-      'linux_chromeos_specific_gtests',
-      'linux_flavor_specific_chromium_gtests',
-      'non_android_chromium_gtests',
-      'non_network_service_gtests',
-      'viz_chromeos_gtests',
-      'viz_gtests',
-    ],
-
-
     'linux_viz_gtests': [
       'non_viz_fyi_chromium_gtests',
       'non_viz_non_android_fyi_chromium_gtests',

testing/buildbot/waterfalls.pyl

@@ -682,7 +682,7 @@
       },
       'linux-chromeos-dbg': {
         'test_suites': {
-          'gtest_tests': 'linux_chromeos_with_non_network_service_gtests',
+          'gtest_tests': 'linux_chromeos_gtests',
         },
       },
       'linux-chromeos-rel': {