Filter out metadata fields that are not requested in zip archiver

Metadata requests in the chrome.fileSystemProvider API declare what
metadata fields they are requesting (i.e. size, modifiction time, etc).
Fields that are provided but not requested will be logged as warnings.

BUG=721790

Change-Id: Ia2c1c1b39f72048be654069557cfc951c5cfc325
Reviewed-on: https://chromium-review.googlesource.com/c/1313989Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Anand Mistry <amistry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604852}

chrome/browser/resources/chromeos/zip_archiver/js/volume.js

@@ -284,7 +284,7 @@ unpacker.Volume.prototype.onGetMetadataRequested = function(
   if (!entryMetadata)
     onError('NOT_FOUND');
   else
-    onSuccess(entryMetadata);
+    onSuccess(this.filterMetadataEntry_(options, entryMetadata));
 };
 
 /**
@@ -311,7 +311,8 @@ unpacker.Volume.prototype.onReadDirectoryRequested = function(
   // Convert dictionary entries to an array.
   var entries = [];
   for (var entry in directoryMetadata.entries) {
-    entries.push(directoryMetadata.entries[entry]);
+    entries.push(
+        this.filterMetadataEntry_(options, directoryMetadata.entries[entry]));
   }
 
   onSuccess(entries, false /* Last call. */);
@@ -442,3 +443,26 @@ unpacker.Volume.prototype.getEntryMetadata_ = function(entryPath) {
 
   return entryMetadata;
 };
+
+/**
+ * Filters the metadata based on the request options.
+ * @param {Object} options Options for the metadata request.
+ * @param {Object} entry Metadata entry to filter.
+ * @return {Object} The filtered metadata.
+ * @private
+ */
+unpacker.Volume.prototype.filterMetadataEntry_ = function(options, entry) {
+  // Make a copy of the entry so that the original remains unchanged.
+  var filteredEntry = Object.assign({}, entry);
+
+  if (!options.isDirectory)
+    delete filteredEntry.isDirectory;
+  if (!options.name)
+    delete filteredEntry.name;
+  if (!options.size)
+    delete filteredEntry.size;
+  if (!options.modificationTime)
+    delete filteredEntry.modificationTime;
+
+  return filteredEntry;
+};