Previously, all FunctionBrokers used the same global set of type marshalers to handle IPC. The marshaling behavior is endpoint-dependent so it is done with the EndpointHandler. This patch makes the EndpointHandler used by a specific RPC function into a template parameter to the function's FunctionBroker. It also divides up the current special type handling into two cases -- FileDlgEndpointHandler for plugin file dialog brokering, and SslEndpointHandler for SSL communication brokering.
Instead of contending with the idiosyncracies of the platform implementations of condition variables, which have been leading to strange crashes, we hold this mutex as a ref-counted object and avoid complex object lifetime reasoning.
The Monitor's Wait call is subject to spurious waking and needed a condition guard (I just use a boolean) to detect if it should not have been awakened. Additionally, the ok value was being assigned after the Notify, despite it no longer being valid on this thread.
The Monitor's condition variable could be notified before the calling thread had begun to Wait for it. This caused the Notify to be missed, leading to hangs. By grabbing the Monitor in PostToDispatchHelper, we know Wait has been called because, otherwise, the calling thread would still hold the Monitor.
The FunctionBroker is a special kind of FunctionHook that brokers the hooked function on another process. In the child process, it uses the FunctionBrokerChild to request that the FunctionBrokerParent run a function and return the response. It handles most cases of parameter, return value and error marshaling on its own. It also guarantees that requests are issued from the proper thread.
