Adds sync brokering to Windows EDK

mojo/edk/system/broker_host.h

Index: mojo/edk/system/broker_host.h
diff --git a/mojo/edk/system/broker_host.h b/mojo/edk/system/broker_host.h
index b8f68c4ddeb36c45821dbcef98a76fa7fdfda06e..74fb917f2978f2b55dfb187dd351c40b6593438b 100644
--- a/mojo/edk/system/broker_host.h
+++ b/mojo/edk/system/broker_host.h
@@ -7,6 +7,8 @@
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
+#include "base/process/process_handle.h"
+#include "mojo/edk/embedder/platform_handle_vector.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/channel.h"
 
@@ -18,7 +20,7 @@ namespace edk {
 class BrokerHost : public Channel::Delegate,
                    public base::MessageLoop::DestructionObserver {
  public:
-  explicit BrokerHost(ScopedPlatformHandle platform_handle);
+  BrokerHost(base::ProcessHandle client_process, ScopedPlatformHandle handle);
 
   // Send |handle| to the child, to be used to establish a NodeChannel to us.
   void SendChannel(ScopedPlatformHandle handle);
@@ -26,6 +28,8 @@ class BrokerHost : public Channel::Delegate,
  private:
   ~BrokerHost() override;
 
+  void PrepareHandlesForClient(PlatformHandleVector* handles);
+
   // Channel::Delegate:
   void OnChannelMessage(const void* payload,
                         size_t payload_size,
@@ -37,6 +41,10 @@ class BrokerHost : public Channel::Delegate,
 
   void OnBufferRequest(size_t num_bytes);
 
+#if defined(OS_WIN)
+  base::ProcessHandle client_process_;
+#endif
+
   scoped_refptr<Channel> channel_;
 
   DISALLOW_COPY_AND_ASSIGN(BrokerHost);