Fix two DCHECKs with WebLayer on desktop.

1) we're not configuring cookie encryption on desktop, so disable it there as the keys will be missing
2) system_network_context_.BindNewPipeAndPassReceiver would dcheck on process crash because it needed to be reset first

Change-Id: I7358a0f16e3d78c99216bc6bff1a4362495093ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017934
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Auto-Submit: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734761}

weblayer/browser/system_network_context_manager.cc

@@ -4,6 +4,7 @@
 
 #include "weblayer/browser/system_network_context_manager.h"
 
+#include "build/build_config.h"
 #include "content/public/browser/network_service_instance.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
 
@@ -87,6 +88,7 @@ void SystemNetworkContextManager::OnNetworkServiceCreated(
     network::mojom::NetworkService* network_service) {
   // The system NetworkContext must be created first, since it sets
   // |primary_network_context| to true.
+  system_network_context_.reset();
   network_service->CreateNetworkContext(
       system_network_context_.BindNewPipeAndPassReceiver(),
       CreateSystemNetworkContextManagerParams());
@@ -100,6 +102,10 @@ SystemNetworkContextManager::CreateSystemNetworkContextManagerParams() {
 
   network_context_params->context_name = std::string("system");
   network_context_params->primary_network_context = true;
+#if defined(OS_LINUX) || defined(OS_WIN)
+  // We're not configuring the cookie encryption on these platforms yet.
+  network_context_params->enable_encrypted_cookies = false;
+#endif
 
   return network_context_params;
 }