Revert "[iOS] Start unified consent service at startup"

This reverts commit 3b42f46a.

Reason for revert: Crashing internal bots

Test Case '-[GoogleServicesSettingsTestCase testOpeningServicesWhileSignedInAndConsentGiven]' started.
0803/040411.392060:FATAL:unified_consent_service.cc(155)] Check failed: identity_manager_->HasPrimaryAccount().
0   ios_chrome_unified_consent_egtests  0x000000010d19df38 base::debug::StackTrace::StackTrace(unsigned long) + 72
1   ios_chrome_unified_consent_egtests  0x000000010d19df9d base::debug::StackTrace::StackTrace(unsigned long) + 29
2   ios_chrome_unified_consent_egtests  0x000000010ce8adac base::debug::StackTrace::StackTrace() + 28
3   ios_chrome_unified_consent_egtests  0x000000010ced068b logging::LogMessage::~LogMessage() + 315
4   ios_chrome_unified_consent_egtests  0x000000010cecf495 logging::LogMessage::~LogMessage() + 21
5   ios_chrome_unified_consent_egtests  0x000000011054785e unified_consent::UnifiedConsentService::OnUnifiedConsentGivenPrefChanged() + 638

Original change's description:
> [iOS] Start unified consent service at startup
> 
> Bug: 827072
> Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
> Change-Id: I2f2e14ceba73ebecbc9c0222ae87ea86e4f91a49
> Reviewed-on: https://chromium-review.googlesource.com/1159062
> Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
> Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
> Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#580485}

TBR=msarda@chromium.org,sdefresne@chromium.org,jlebel@chromium.org

Change-Id: I4d94ba1e7630c81f666d336882c17c993ac5ef02
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 827072
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Reviewed-on: https://chromium-review.googlesource.com/1162402Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580635}

ios/chrome/browser/browser_state/BUILD.gn

@@ -116,7 +116,6 @@ source_set("browser_state_impl") {
     "//ios/chrome/browser/ui/overlays",
     "//ios/chrome/browser/ui/voice",
     "//ios/chrome/browser/undo",
-    "//ios/chrome/browser/unified_consent:unified_consent",
     "//ios/net",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser/signin",

ios/chrome/browser/browser_state/chrome_browser_state_manager_impl.cc

@@ -41,7 +41,6 @@
 #include "ios/chrome/browser/signin/gaia_cookie_manager_service_factory.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #include "ios/chrome/browser/sync/profile_sync_service_factory.h"
-#include "ios/chrome/browser/unified_consent/unified_consent_service_factory.h"
 
 namespace {
 
@@ -224,9 +223,6 @@ void ChromeBrowserStateManagerImpl::DoFinalInitForServices(
   ios::AccountFetcherServiceFactory::GetForBrowserState(browser_state)
       ->SetupInvalidationsOnProfileLoad(invalidation_service);
   ios::AccountReconcilorFactory::GetForBrowserState(browser_state);
-  // Initialization needs to happen after the browser context is available
-  // because ProfileSyncService needs the URL context getter.
-  UnifiedConsentServiceFactory::GetForBrowserState(browser_state);
   DesktopPromotionSyncServiceFactory::GetForBrowserState(browser_state);
 }