[Cronet] Move initialization to a new thread rather than the UI thread.

components/cronet/android/cronet_library_loader.h

Index: components/cronet/android/cronet_library_loader.h
diff --git a/components/cronet/android/cronet_library_loader.h b/components/cronet/android/cronet_library_loader.h
index 7e3ab3dff2a5c8495497faadda435b3048de6c3d..5f5ece85e208c2c0bf971811555ea76fef66406a 100644
--- a/components/cronet/android/cronet_library_loader.h
+++ b/components/cronet/android/cronet_library_loader.h
@@ -12,6 +12,10 @@ namespace cronet {
 jint CronetOnLoad(JavaVM* vm, void* reserved);
 void CronetOnUnLoad(JavaVM* jvm, void* reserved);
 
+// Returns true when running on initialization thread.
+// Only callable after initialization thread is started.
+bool OnInitThread();
+
 }  // namespace cronet
 
 #endif  // COMPONENTS_CRONET_ANDROID_CRONET_LIBRARY_LOADER_H_