Add getDefaultFontSize and setDefaultFontSize to Font Settings Extension API.

chrome/common/extensions/api/experimental.fontSettings.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "experimental.fontSettings",
     "types": [
       {
         "id": "FontName",
@@ skipping 107 matching lines @@
             "name": "callback",
             "parameters": [
               {
                 "name": "results",
                 "type": "array",
                 "items": { "$ref": "FontName" }
               }
             ]
           }
         ]
+      },
+      {
+        "name": "getDefaultFontSize",
+        "type": "function",
+        "description": "Gets the default font size.",
+        "parameters": [
+          {
+            "name": "details",
+            "type": "object",
+            "description": "This parameter is currently unused."

[Matt Perry, 2012/03/23 18:32:53]

Just remove this param if its not used. Do you have plans to make use of it?

[falken, 2012/03/24 04:27:13]

Yes, I think eventually we want the font size prefs to also be per-script, at
least for minimum font size (http://crbug.com/17078). I figure reserving this
parameter would make it less disruptive to extend the API if that happens.

[Matt Perry, 2012/03/26 18:31:18]

OK, makes sense. Do you foresee it being optional? (i.e. omitting it means "get
font size for all fonts" ?) If so, I'd make it optional now. Otherwise, this is
good.

[falken, 2012/03/27 02:04:11]

OK, I'll make it optional in the next patch
(http://codereview.chromium.org/9853013/). I thought it would have to be
specified whenever the callback is specified (due to the order of parameters),
but it seems to work.

+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": "true",
+            "parameters": [
+              {
+                "name": "details",
+                "type": "object",
+                "properties": {
+                  "pixelSize": {
+                    "type": "integer",
+                    "description": "The font size in pixels."
+                  }
+                }
+              }
+            ]
+          }
+        ]
+      },
+      {
+        "name": "setDefaultFontSize",
+        "type": "function",
+        "description": "Sets the default font size.",
+        "parameters": [
+          {
+            "name": "details",
+            "type": "object",
+            "properties": {
+              "pixelSize": {
+                "type": "integer",
+                "description": "The font size in pixels."
+              }
+            }
+          },
+          {
+            "type": "function",
+            "name": "callback",
+            "optional": "true",
+            "parameters": []
+          }
+        ]
       }
     ]
   }
 ]