Add VideoPacket struct for video packets. Refactor Decode interface to use it.

remoting/proto/internal.proto

Index: remoting/proto/internal.proto
diff --git a/remoting/proto/internal.proto b/remoting/proto/internal.proto
index fbe3181ea6c2e137da068ca53b77328c5bc50651..7a8e908f40d9a4f6cb9266510b2d02d5289bd149 100644
--- a/remoting/proto/internal.proto
+++ b/remoting/proto/internal.proto
@@ -6,6 +6,7 @@
 
 syntax = "proto2";
 
+import "control.proto";
 import "event.proto";
 import "video.proto";
 
@@ -13,14 +14,6 @@ option optimize_for = LITE_RUNTIME;
 
 package remoting;
 
-// Defines the message that is sent from the host to the client.
-// Only one of these messages should be present.
-// NEXT ID: 5
-message ChromotingHostMessage {
-  optional InitClientMessage init_client= 1;
-  optional VideoPacket video_packet = 2;
-}
-
 // Defines the message that is sent from the client to the host.
 // Only one of the optional messages should be present.
 // NEXT ID: 7