Refactor implementation of BrowserActions, and add support for

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "types": [
       {
         "id": "Port",
         "type": "object",
         "description": "An object which allows two way communication with other pages.",
         "properties": {
           "name": {"type": "string"},
@@ skipping 851 matching lines @@
           {
             "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."},
               "imageData": {
                 "type": "any",
                 "description": "Pixel data for an image. Must be an ImageData object (for example, from a canvas element).",
                 "optional": true
               },
+              "path": {
+                "type": "string",
+                "description": "Relative path to an image in the extension to show in the browser action.",
+                "optional": true
+              },
               "iconIndex": {
                 "type": "integer",
                 "minimum": 0,
                 "description": "<b>Deprecated.</b> The zero-based index into the <b>icons</b> vector specified in the manifest.",
                 "optional": true
               }
             }
           }
         ]
       },
@@ skipping 86 matching lines @@
         "type": "function",
         "description": "Sets the title of the browser action. This shows up in the tooltip.",
         "parameters": [
           {
             "name": "details",
             "type": "object",
             "properties": {
               "title": {
                 "type": "string",
                 "description": "The string the browser action should display when moused over."
+              },
+              "tabId": {
+                "type": "integer",
+                "optional": true,
+                "description": "Limits the change to when a particular tab is selected. Automatically resets when the tab is closed."
               }
             }
           }
         ]
       },
       {
         "name": "setIcon",
         "type": "function",
         "description": "Sets the icon for the browser action. The icon can be specified either as the path to an image file or as the pixel data from a canvas element. Either the <b>path</b> or the <b>imageData</b> property must be specified.",
         "parameters": [
           {
             "name": "details",
             "type": "object",
             "properties": {
               "imageData": {
                 "type": "any",
                 "description": "Pixel data for an image. Must be an ImageData object (for example, from a <code>canvas</code> element).",
                 "optional": true
               },
-              "iconIndex": {
-                "type": "integer",
-                "minimum": 0,
-                "description": "<b>Deprecated.</b> The zero-based index into the <b>icons</b> vector specified in the manifest.",
-                "optional": true
-              },
               "path": {
                 "type": "string",
                 "description": "Relative path to an image in the extension to show in the browser action.",
                 "optional": true
+              },
+              "tabId": {
+                "type": "integer",
+                "optional": true,
+                "description": "Limits the change to when a particular tab is selected. Automatically resets when the tab is closed."
               }
             }
           }
         ]
       },
       {
         "name": "setBadgeText",
         "type": "function",
         "description": "Sets the badge text for the browser action. The badge is displayed on top of the icon.",
         "parameters": [
           {
             "name": "details",
             "type": "object",
             "properties": {
               "text": {
                 "type": "string",
                 "description": "Any number of characters can be passed, but only about four can fit in the space."
+              },
+              "tabId": {
+                "type": "integer",
+                "optional": true,
+                "description": "Limits the change to when a particular tab is selected. Automatically resets when the tab is closed."
               }
             }
           }
         ]
       },
       {
         "name": "setBadgeBackgroundColor",
         "type": "function",
         "description": "Sets the background color for the badge.",
         "parameters": [
           {
             "name": "details",
             "type": "object",
             "properties": {
               "color": {
                 "type": "array",
                 "description": "An array of four integers in the range [0,255] that make up the RGBA color of the badge. For example, opaque red is <code>[255, 0, 0, 255]</code>.",
                 "items": {
                   "type": "integer",
                   "minimum": 0,
                   "maximum": 255
                 },
                 "minItems": 4,
                 "maxItems": 4
+              },
+              "tabId": {
+                "type": "integer",
+                "optional": true,
+                "description": "Limits the change to when a particular tab is selected. Automatically resets when the tab is closed."
               }
             }
           }
         ]
       }
     ],
     "events": [
       {
         "name": "onClicked",
         "type": "function",
@@ skipping 399 matching lines @@
         "type": "function",
         "description": "Logs a message during internal unit testing.",
         "parameters": [
           {"type": "string", "name": "message"}
         ]
       }
     ],
     "events": []
   }
 ]