Revert "Revert "Disable Channel ID on all platforms except Android""

This reverts commit 3c79bfc0.

In addition to the original CL bd3d1ea0, this includes a fix to the crash
when relaunching after changing about:flags.

Bug: 841006
Change-Id: I04c82074bb83da7ba5854b783862ec689d7a36e0
Reviewed-on: https://chromium-review.googlesource.com/1050976Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Commit-Queue: Nick Harper <nharper@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557307}

components/network_session_configurator/common/network_features.cc

@@ -4,12 +4,19 @@
 
 #include "components/network_session_configurator/common/network_features.h"
 
+#include "build/build_config.h"
+
 namespace features {
 
 const base::Feature kTokenBinding{"token-binding",
                                   base::FEATURE_DISABLED_BY_DEFAULT};
 
+#if defined(OS_ANDROID)
+// TODO(nharper): Disable kChannelID on all platforms in M69.
 const base::Feature kChannelID{"channel-id", base::FEATURE_ENABLED_BY_DEFAULT};
+#else
+const base::Feature kChannelID{"channel-id", base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  // defined(OS_ANDROID)
 
 const base::Feature kDnsOverHttps{"dns-over-https",
                                   base::FEATURE_DISABLED_BY_DEFAULT};

content/browser/browser_context.cc

@@ -143,8 +143,11 @@ void SaveSessionStateOnIOThread(
     AppCacheServiceImpl* appcache_service) {
   net::URLRequestContext* context = context_getter->GetURLRequestContext();
   context->cookie_store()->SetForceKeepSessionState();
-  context->channel_id_service()->GetChannelIDStore()->
-      SetForceKeepSessionState();
+  if (context->channel_id_service()) {
+    context->channel_id_service()
+        ->GetChannelIDStore()
+        ->SetForceKeepSessionState();
+  }
   appcache_service->set_force_keep_session_state();
 }