[WIP][PPAPI] Implement MediaStreamVideoTrackResource.

ppapi/proxy/plugin_var_tracker.cc

Index: ppapi/proxy/plugin_var_tracker.cc
diff --git a/ppapi/proxy/plugin_var_tracker.cc b/ppapi/proxy/plugin_var_tracker.cc
index a9cbd9c7a62bd2e6fdefc9b4b7f4d2c552ed8ba6..2d88f9ca779e8158876130e544fe8fb0c85a490e 100644
--- a/ppapi/proxy/plugin_var_tracker.cc
+++ b/ppapi/proxy/plugin_var_tracker.cc
@@ -10,6 +10,7 @@
 #include "ppapi/c/dev/ppp_class_deprecated.h"
 #include "ppapi/c/ppb_var.h"
 #include "ppapi/proxy/file_system_resource.h"
+#include "ppapi/proxy/media_stream_video_track_resource.h"
 #include "ppapi/proxy/plugin_array_buffer_var.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/plugin_globals.h"
@@ -172,10 +173,10 @@ PP_Var PluginVarTracker::MakeResourcePPVarFromMessage(
     const IPC::Message& creation_message,
     int pending_renderer_id,
     int pending_browser_id) {
-  DCHECK(pending_renderer_id);
-  DCHECK(pending_browser_id);
   switch (creation_message.type()) {
     case PpapiPluginMsg_FileSystem_CreateFromPendingHost::ID: {
+      DCHECK(pending_renderer_id);
+      DCHECK(pending_browser_id);
       PP_FileSystemType file_system_type;
       if (!UnpackMessage<PpapiPluginMsg_FileSystem_CreateFromPendingHost>(
                creation_message, &file_system_type)) {
@@ -194,6 +195,22 @@ PP_Var PluginVarTracker::MakeResourcePPVarFromMessage(
                                   file_system_type))->GetReference();
       return MakeResourcePPVar(pp_resource);
     }
+    case PpapiPluginMsg_MediaStreamVideoTrack_CreateFromPendingHost::ID: {
+      DCHECK(pending_renderer_id);
+      std::string id;
+      if (!UnpackMessage<
+              PpapiPluginMsg_MediaStreamVideoTrack_CreateFromPendingHost>(
+          creation_message, &id)) {
+        NOTREACHED() <<
+          "Invalid message of type "
+          "PpapiPluginMsg_MediaStreamVideoTrack_CreateFromPendingHost";
+        return PP_MakeNull();
+      }
+      MediaStreamVideoTrackResource *resource =
+        new MediaStreamVideoTrackResource(GetConnectionForInstance(instance),
+                                          instance, pending_renderer_id, id);
+      return MakeResourcePPVar(resource->GetReference());
+    }
     default: {
       NOTREACHED() << "Creation message has unexpected type "
                    << creation_message.type();