[fsp] Add a method to enumerate all mounted file systems.

chrome/common/extensions/api/file_system_provider.idl

Index: chrome/common/extensions/api/file_system_provider.idl
diff --git a/chrome/common/extensions/api/file_system_provider.idl b/chrome/common/extensions/api/file_system_provider.idl
index ec87d20b922973779fe4f8fb3d871bd700e8409a..b0260735ef07f0127b73bb9a99d76911d7ac09a8 100644
--- a/chrome/common/extensions/api/file_system_provider.idl
+++ b/chrome/common/extensions/api/file_system_provider.idl
@@ -53,6 +53,13 @@ namespace fileSystemProvider {
     DOMString? mimeType; 
   };
 
+  // Represents a mounted file system.
+  dictionary FileSystemInfo {
+    DOMString fileSystemId;
+    DOMString displayName;
+    [nodoc] boolean writable;
+  };
+
   // Options for the <code>mount()</code> method.
   dictionary MountOptions {
     DOMString fileSystemId;
@@ -173,6 +180,9 @@ namespace fileSystemProvider {
   // Callback to receive the result of unmount() function.
   callback UnmountCallback = void([nodoc, instanceOf=DOMError] object error);
 
+  // Callback to receive the result of getAll() function.
+  callback GetAllCallback = void(FileSystemInfo[] fileSystems);
+
   // Callback to handle an error raised from the browser.
   [nocompile] callback ErrorCallback = void([instanceOf=DOMError] object error);
 
@@ -222,6 +232,9 @@ namespace fileSystemProvider {
     static void unmount(UnmountOptions options,
                         UnmountCallback successCallback,
                         [nocompile] ErrorCallback errorCallback);
+
+    // Returns all file systems mounted by the extension.
+    static void getAll(GetAllCallback callback);
   };
 
   interface Events {