Revert "[Previews] Add offline check before HintsFetch."

This reverts commit
b58c0181 (crrev.com/c/1715505).

Reason for revert: causes crashes in browser_tests (crbug.com/988887).

Bug: 988887
Change-Id: Iacb009a129c66c905b15b4f81544d3ad25706de6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1725323
Auto-Submit: Bob Haarman <inglorion@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Reviewed-by: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682162}

chrome/browser/previews/hints_fetcher_browsertest.cc

@@ -40,7 +40,6 @@
 #include "components/previews/core/previews_switches.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/test/browser_test_utils.h"
-#include "content/public/test/network_connection_change_simulator.h"
 #include "net/test/embedded_test_server/http_request.h"
 #include "net/test/embedded_test_server/http_response.h"
 #include "services/network/public/cpp/network_quality_tracker.h"
@@ -169,11 +168,6 @@ class HintsFetcherDisabledBrowserTest : public InProcessBrowserTest {
     run_loop.Run();
   }
 
-  void SetNetworkConnectionOffline() {
-    content::NetworkConnectionChangeSimulator().SetConnectionType(
-        network::mojom::ConnectionType::CONNECTION_NONE);
-  }
-
   // Seeds the Site Engagement Service with two HTTP and two HTTPS sites for the
   // current profile.
   void SeedSiteEngagementService() {
@@ -658,30 +652,3 @@ IN_PROC_BROWSER_TEST_F(
           optimization_guide::HintCacheStore::StoreEntryType::kComponentHint),
       0);
 }
-
-IN_PROC_BROWSER_TEST_F(
-    HintsFetcherBrowserTest,
-    DISABLE_ON_WIN_MAC_CHROMESOS(HintsFetcherNetworkOffline)) {
-  const base::HistogramTester* histogram_tester = GetHistogramTester();
-  GURL url = https_url();
-  base::CommandLine::ForCurrentProcess()->RemoveSwitch(
-      optimization_guide::switches::kFetchHintsOverride);
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      optimization_guide::switches::kFetchHintsOverrideTimer);
-
-  // Set the network to be offline.
-  SetNetworkConnectionOffline();
-
-  // Set the blacklist state to initialized so the sites in the engagement
-  // service will be used and not blacklisted on the first GetTopHosts
-  // request.
-  SetTopHostBlacklistState(optimization_guide::prefs::
-                               HintsFetcherTopHostBlacklistState::kInitialized);
-
-  // Whitelist NoScript for https_url()'s' host.
-  SetUpComponentUpdateHints(https_url());
-
-  // No HintsFetch should occur because the connection is offline.
-  histogram_tester->ExpectTotalCount(
-      "OptimizationGuide.HintsFetcher.GetHintsRequest.HostCount", 0);
-}

components/optimization_guide/BUILD.gn

@@ -2,8 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-assert(!is_ios, "Optimization Guide is not available on iOS.")
-
 static_library("optimization_guide") {
   sources = [
     "bloom_filter.cc",
@@ -44,7 +42,6 @@ static_library("optimization_guide") {
     "//components/leveldb_proto",
     "//components/optimization_guide/proto:optimization_guide_proto",
     "//components/prefs",
-    "//content/public/browser",
     "//google_apis",
     "//net:net",
     "//services/network/public/cpp",

components/optimization_guide/DEPS

 include_rules = [
   "+components/leveldb_proto",
   "+components/prefs",
-  "+content/public/browser",
   "+google_apis",
   "+net",
   "+services/network",

components/optimization_guide/hints_fetcher.cc

@@ -12,12 +12,12 @@
 #include "base/metrics/histogram_macros.h"
 #include "components/optimization_guide/optimization_guide_features.h"
 #include "components/optimization_guide/proto/hints.pb.h"
-#include "content/public/browser/network_service_instance.h"
 #include "net/base/load_flags.h"
 #include "net/base/url_util.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
+#include "net/traffic_annotation/network_traffic_annotation.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
 #include "services/network/public/cpp/simple_url_loader.h"
 
@@ -42,11 +42,6 @@ bool HintsFetcher::FetchOptimizationGuideServiceHints(
     HintsFetchedCallback hints_fetched_callback) {
   SEQUENCE_CHECKER(sequence_checker_);
 
-  if (content::GetNetworkConnectionTracker()->IsOffline()) {
-    std::move(hints_fetched_callback_).Run(base::nullopt);
-    return false;
-  }
-
   if (url_loader_)
     return false;