Add tabs.onReplaced event to notify listeners of tabs being swapped due to prerendering or instant.

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..2aa3848d596fb0402ef0fda874888b1f5abe9c2a 100644
--- a/chrome/common/extensions/api/tabs.json
+++ b/chrome/common/extensions/api/tabs.json
@@ -918,6 +918,15 @@
             }
           }
         ]
+      },
+      {
+        "name": "onSwapped",

[Matt Perry, 2012/12/18 18:04:02]

nit: I have a slight preference for onReplaced.

[justinlin, 2012/12/19 23:42:42]

Done. Yea, sounds better.

+        "type": "function",
+        "description": "Fired when a tab is replaced with another tab due to prerendering or instant.",
+        "parameters": [
+          {"type": "integer", "name": "addedTabId", "minimum": 0},
+          {"type": "integer", "name": "removedTabId", "minimum": 0}
+        ]
       }
     ]
   }