Allow extensions to add, remove, or change their page action popup.

chrome/common/extensions/api/extension_api.json

Index: chrome/common/extensions/api/extension_api.json
diff --git a/chrome/common/extensions/api/extension_api.json b/chrome/common/extensions/api/extension_api.json
index 5a3e6c5aa0f579f29eb98098688e295f4f05ae55..80bf2312f93146fc0321ccb2c6a9e7896b7730d8 100755
--- a/chrome/common/extensions/api/extension_api.json
+++ b/chrome/common/extensions/api/extension_api.json
@@ -1002,13 +1002,31 @@
             }
           }
         ]
+      },
+      {
+        "name": "setPopup",
+        "type": "function",
+        "description": "Sets the html document to be opened as a popup when the user clicks on the page action's icon.",
+        "parameters": [
+          {
+            "name": "details",
+            "type": "object",
+            "properties": {
+              "tabId": {"type": "integer", "minimum": 0, "description": "The id of the tab for which you want to modify the page action."},
+              "popup": {
+                "type": "string",
+                "description": "The html file to show in a popup.  If set to the empty string (''), no popup is shown."
+              }
+            }
+          }
+        ]
       }
     ],
     "events": [
       {
         "name": "onClicked",
         "type": "function",
-        "description": "Fired when a page action icon is clicked.",
+        "description": "Fired when a page action icon is clicked if the page action doesn't show a popup.",
         "parameters": [
           {
             "name": "tab",