extensions: tabs: set tab id to -1 for app/devtools windows

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 defeb1c09180bcef5ace2fbabd89a885b0eee93f..b1c70635cdb9c9efe098e08d8eaf11b40a2c312e 100644
--- a/chrome/common/extensions/api/tabs.json
+++ b/chrome/common/extensions/api/tabs.json
@@ -11,7 +11,7 @@
         "id": "Tab",
         "type": "object",
         "properties": {
-          "id": {"type": "integer", "minimum": 0, "optional": true, "description": "The ID of the tab. Tab IDs are unique within a browser session. Under some circumstances a Tab may not be assigned an ID, for example when querying foreign tabs using the $(ref:sessions) API, in which case a session ID may be present."},
+          "id": {"type": "integer", "minimum": -1, "optional": true, "description": "The ID of the tab. Tab IDs are unique within a browser session. Under some circumstances a Tab may not be assigned an ID, for example when querying foreign tabs using the $(ref:sessions) API, in which case a session ID may be present. Tab ID can also be set to chrome.tabs.TAB_ID_NONE for applications and devtools windows."},

[not at google - send to devlin, 2015/07/17 16:44:58]

"applications" --> "apps"

[llandwerlin-old, 2015/07/17 17:05:04]

Done.

           // TODO(kalman): Investigate how this is ending up as -1 (based on window type? a bug?) and whether it should be optional instead.
           "index": {"type": "integer", "minimum": -1, "description": "The zero-based index of the tab within its window."},
           "windowId": {"type": "integer", "minimum": 0, "description": "The ID of the window the tab is contained within."},
@@ -102,6 +102,12 @@
         "description": "The type of window."
       }
     ],
+    "properties": {
+      "TAB_ID_NONE": {
+        "value": -1,
+        "description": "The id value that represents the absence of a chrome browser tab."

[not at google - send to devlin, 2015/07/17 16:44:58]

"The id value that" --> "An ID which"
"chrome" --> "Chrome"

[llandwerlin-old, 2015/07/17 17:05:04]

Done.

+      }
+    },
     "functions": [
       {
         "name": "get",