Update references to the extension messaging APIs to point to the "runtime"

chrome/common/extensions/api/tabs.json

Index: chrome/common/extensions/api/tabs.json
diff --git a/chrome/common/extensions/api/tabs.json b/chrome/common/extensions/api/tabs.json
index 16dd03526e665b2bb6fe7d57bda3f5f35c71e4d5..a86d3962f55dff8908e5c007744c347dc14933c0 100644
--- a/chrome/common/extensions/api/tabs.json
+++ b/chrome/common/extensions/api/tabs.json
@@ -85,7 +85,7 @@
         "name": "connect",
         "nocompile": true,
         "type": "function",
-        "description": "Connects to the content script(s) in the specified tab. The $ref:extension.onConnect event is fired in each content script running in the specified tab for the current extension. For more details, see <a href='content_scripts.html#messaging'>Content Script Messaging</a>.",
+        "description": "Connects to the content script(s) in the specified tab. The $ref:runtime.onConnect event is fired in each content script running in the specified tab for the current extension. For more details, see <a href='content_scripts.html#messaging'>Content Script Messaging</a>.",
         "parameters": [
           {
             "type": "integer",
@@ -102,8 +102,8 @@
           }
         ],
         "returns": {
-          "$ref": "extension.Port",
-          "description": "A port that can be used to communicate with the content scripts running in the specified tab. The port's $ref:extension.Port event is fired if the tab closes or does not exist. "
+          "$ref": "runtime.Port",
+          "description": "A port that can be used to communicate with the content scripts running in the specified tab. The port's $ref:runtime.Port event is fired if the tab closes or does not exist. "
         }
       },
       {
@@ -140,7 +140,7 @@
         "name": "sendMessage",
         "nocompile": true,
         "type": "function",
-        "description": "Sends a single message to the content script(s) in the specified tab, with an optional callback to run when a response is sent back.  The $ref:extension.onMessage event is fired in each content script running in the specified tab for the current extension.",
+        "description": "Sends a single message to the content script(s) in the specified tab, with an optional callback to run when a response is sent back.  The $ref:runtime.onMessage event is fired in each content script running in the specified tab for the current extension.",
         "parameters": [
           {
             "type": "integer",