[Cronet] Delay StartNetLog and StopNetLog until native request context is initialized

components/cronet/android/cronet_url_request_context_adapter.cc

Index: components/cronet/android/cronet_url_request_context_adapter.cc
diff --git a/components/cronet/android/cronet_url_request_context_adapter.cc b/components/cronet/android/cronet_url_request_context_adapter.cc
index 1a633587b2597fc5603e738c4a95520496c68d10..a176c1920cefa4dae445adc5cffd2442513c7199 100644
--- a/components/cronet/android/cronet_url_request_context_adapter.cc
+++ b/components/cronet/android/cronet_url_request_context_adapter.cc
@@ -265,7 +265,7 @@ CronetURLRequestContextAdapter::GetNetworkTaskRunner() const {
 void CronetURLRequestContextAdapter::StartNetLogToFile(JNIEnv* env,
                                                        jobject jcaller,
                                                        jstring jfile_name) {
-  GetNetworkTaskRunner()->PostTask(
+  PostTaskToNetworkThread(
       FROM_HERE,
       base::Bind(
           &CronetURLRequestContextAdapter::StartNetLogToFileOnNetworkThread,
@@ -274,7 +274,7 @@ void CronetURLRequestContextAdapter::StartNetLogToFile(JNIEnv* env,
 }
 
 void CronetURLRequestContextAdapter::StopNetLog(JNIEnv* env, jobject jcaller) {
-  GetNetworkTaskRunner()->PostTask(
+  PostTaskToNetworkThread(
       FROM_HERE,
       base::Bind(&CronetURLRequestContextAdapter::StopNetLogOnNetworkThread,
                  base::Unretained(this)));