Add chrome.fileSystem.GetVolumeList().

chrome/common/extensions/api/file_system.idl

Index: chrome/common/extensions/api/file_system.idl
diff --git a/chrome/common/extensions/api/file_system.idl b/chrome/common/extensions/api/file_system.idl
index a39dd01e83849b07ce0e99a99301cbc3fdeb6452..45868ca4fe41af5659677db11c94df67f5ca46e8 100644
--- a/chrome/common/extensions/api/file_system.idl
+++ b/chrome/common/extensions/api/file_system.idl
@@ -83,7 +83,7 @@ namespace fileSystem {
     boolean? acceptsMultiple;
   };
 
-  dictionary RequestFileSystemOptions {
+  [nodoc] dictionary RequestFileSystemOptions {
     // The ID of the requested volume.
     DOMString volumeId;
 
@@ -92,7 +92,14 @@ namespace fileSystem {
     boolean? writable;
   };
 
-// Change to an entry within a tracked directory.
+  // Represents a mounted volume, which can be accessed via <code>chrome.
+  // fileSystem.requestFileSystem</code>.
+  [nodoc] dictionary Volume {
+    DOMString volumeId;
+    boolean writable;
+  };
+
+  // Change to an entry within a tracked directory.
   [nodoc] dictionary ChildChange {
     [instanceOf=Entry] object entry;
     ChildChangeType type;
@@ -125,6 +132,7 @@ namespace fileSystem {
       [instanceOf=Entry] object[] entries);
   [nodoc] callback RequestFileSystemCallback = void(
       [instanceOf=FileSystem] optional object fileSystem);
+  [nodoc] callback GetVolumeListCallback = void(optional Volume[] volumes);

[benwells, 2015/04/07 05:43:13]

Nit: should  this be optional? I think if the call succeeds (i.e. no error)
there should be a list so you can drop optional. I could be wrong abotu that
though.

[mtomasz, 2015/04/07 07:35:35]

Good point. Done.

 
   interface Functions {
     // Get the display path of an Entry object. The display path is based on
@@ -175,6 +183,12 @@ namespace fileSystem {
     [nodoc] static void requestFileSystem(RequestFileSystemOptions options,
                                           RequestFileSystemCallback callback);
 
+    // Returns a list of volumes available for <code>requestFileSystem()</code>.
+    // The <code>"fileSystem": {"requestFileSystem"}</code> manifest permission
+    // is required. permission in the manifest. Available to kiosk apps running

[benwells, 2015/04/07 05:43:13]

Nit: I think you want to delete ' permission in the manifest.'

[mtomasz, 2015/04/07 07:35:35]

Done.

+    // in the kiosk session only.
+    [nodoc] static void getVolumeList(GetVolumeListCallback callback);
+
     // Observes a directory entry. Emits an event if the tracked directory is
     // changed (including the list of files on it), or removed. If <code>
     // recursive</code> is set to true, then also all accessible subdirectories