Fix comparison function when sorting volumes in tests

The following CL changed how Array.p.sort works in JS:
http://crrev.com/c/1151199

This broke some file manager tests. The reason is a broken comparison
function when sorting the volumes for the tests. JS needs a comparsion
function that returns < 0,0 or > 0 if a value is less than, equal to or
greater than another one respectively. This CL fixes that.

R=joelhockey@chromium.org

Change-Id: I08c4ebf352d3e8ec984239edd01f39eac261e576
Reviewed-on: https://chromium-review.googlesource.com/1184848Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#585419}

chrome/test/data/extensions/api_test/file_browser/file_watcher_test/test.js

@@ -235,7 +235,7 @@ function initTests(callback) {
     var sortedVolumeMetadataList = volumeMetadataList.filter(function(volume) {
       return possibleVolumeTypes.indexOf(volume.volumeType) != -1;
     }).sort(function(volumeA, volumeB) {
-      return possibleVolumeTypes.indexOf(volumeA.volumeType) >
+      return possibleVolumeTypes.indexOf(volumeA.volumeType) -
              possibleVolumeTypes.indexOf(volumeB.volumeType);
     });
 

chrome/test/data/extensions/api_test/file_browser/filesystem_operations_test/test.js

@@ -490,7 +490,7 @@ function initTests(callback) {
     var sortedVolumeMetadataList = volumeMetadataList.filter(function(volume) {
       return possibleVolumeTypes.indexOf(volume.volumeType) != -1;
     }).sort(function(volumeA, volumeB) {
-      return possibleVolumeTypes.indexOf(volumeA.volumeType) >
+      return possibleVolumeTypes.indexOf(volumeA.volumeType) -
              possibleVolumeTypes.indexOf(volumeB.volumeType);
     });
 

chrome/test/data/extensions/api_test/file_browser/handler_test_runner/test.js

@@ -194,7 +194,7 @@ function run() {
     var sortedVolumeMetadataList = volumeMetadataList.filter(function(volume) {
       return possibleVolumeTypes.indexOf(volume.volumeType) != -1;
     }).sort(function(volumeA, volumeB) {
-      return possibleVolumeTypes.indexOf(volumeA.volumeType) >
+      return possibleVolumeTypes.indexOf(volumeA.volumeType) -
              possibleVolumeTypes.indexOf(volumeB.volumeType);
     });
     if (sortedVolumeMetadataList.length == 0) {