Fix Cronet tests.

components/cronet/url_request_context_config_unittest.cc

Index: components/cronet/url_request_context_config_unittest.cc
diff --git a/components/cronet/url_request_context_config_unittest.cc b/components/cronet/url_request_context_config_unittest.cc
index 4d17c52858d3ee3f01f7ab043d5ddf45609d82eb..3178058b279f9c344ae7d7b0718976f60a99e0bc 100644
--- a/components/cronet/url_request_context_config_unittest.cc
+++ b/components/cronet/url_request_context_config_unittest.cc
@@ -5,7 +5,7 @@
 #include "components/cronet/url_request_context_config.h"
 
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/values.h"
 #include "net/cert/cert_verifier.h"
 #include "net/http/http_network_session.h"
@@ -19,8 +19,10 @@
 
 namespace cronet {
 
-// Test is flaky. See https://crbug.com/737326.
-TEST(URLRequestContextConfigTest, DISABLED_TestExperimentalOptionParsing) {
+TEST(URLRequestContextConfigTest, TestExperimentalOptionParsing) {
+  base::test::ScopedTaskEnvironment scoped_task_environment_(
+      base::test::ScopedTaskEnvironment::MainThreadType::IO);
+
   URLRequestContextConfig config(
       // Enable QUIC.
       true,
@@ -65,7 +67,6 @@ TEST(URLRequestContextConfigTest, DISABLED_TestExperimentalOptionParsing) {
       // Certificate verifier cache data.
       "");
 
-  base::MessageLoop message_loop;
   net::URLRequestContextBuilder builder;
   net::NetLog net_log;
   config.ConfigureURLRequestContextBuilder(&builder, &net_log, nullptr);
@@ -111,8 +112,10 @@ TEST(URLRequestContextConfigTest, DISABLED_TestExperimentalOptionParsing) {
                          info, &addresses, net::NetLogWithSource()));
 }
 
-// Test is flaky. See https://crbug.com/737326.
-TEST(URLRequestContextConfigTest, DISABLED_SetQuicConnectionMigrationOptions) {
+TEST(URLRequestContextConfigTest, SetQuicConnectionMigrationOptions) {
+  base::test::ScopedTaskEnvironment scoped_task_environment_(
+      base::test::ScopedTaskEnvironment::MainThreadType::IO);
+
   URLRequestContextConfig config(
       // Enable QUIC.
       true,
@@ -147,7 +150,6 @@ TEST(URLRequestContextConfigTest, DISABLED_SetQuicConnectionMigrationOptions) {
       // Certificate verifier cache data.
       "");
 
-  base::MessageLoop message_loop;
   net::URLRequestContextBuilder builder;
   net::NetLog net_log;
   config.ConfigureURLRequestContextBuilder(&builder, &net_log, nullptr);