[FileBrowser] Added DefaultAction dialog to choose default action.

chrome/common/extensions/api/file_browser_private.json

Index: chrome/common/extensions/api/file_browser_private.json
diff --git a/chrome/common/extensions/api/file_browser_private.json b/chrome/common/extensions/api/file_browser_private.json
index 3b28fd858ec4762d822e0cb9e2591af64c7a31e3..e3e9f3b790200eeaa59805ead4bf70bab471697f 100644
--- a/chrome/common/extensions/api/file_browser_private.json
+++ b/chrome/common/extensions/api/file_browser_private.json
@@ -388,6 +388,30 @@
         ]
       },
       {
+        "name": "setDefaultTask",
+        "description": "Sets default task.",
+        "parameters": [
+          {
+            "name": "taskId",
+            "type": "string",
+            "description": "The unique identifier of task to mark as default."
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "success",
+                "type": "boolean",
+                "optional": true,
+                "description": "True if task successfully made default."
+              }
+            ]
+          }
+        ]        
+      },
+      {
         "name": "getFileTasks",
         "description": "Gets the list of tasks that can be performed over selected files.",
         "parameters": [