Support choosing multiple files with fileSystem.chooseEntry.

chrome/renderer/resources/extensions/file_system_custom_bindings.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Custom binding for the fileSystem API.
 
 var binding = require('binding').Binding.create('fileSystem');
 
 var fileSystemNatives = requireNative('file_system_natives');
 var GetIsolatedFileSystem = fileSystemNatives.GetIsolatedFileSystem;
@@ skipping 12 matching lines @@
 // allows them to be used from other windows (including the background page)
 // after the original window is closed.
 if (window == backgroundPage) {
   var bindFileEntryCallback = function(functionName, apiFunctions) {
     apiFunctions.setCustomCallback(functionName,
         function(name, request, response) {
       if (request.callback && response) {
         var callback = request.callback;
         request.callback = null;
 
-        var fileSystemId = response.fileSystemId;
-        var baseName = response.baseName;
-        var id = response.id;
-        var fs = GetIsolatedFileSystem(fileSystemId);
+        var entries = [];
+        var hasError = false;
 
-        try {
-          // TODO(koz): fs.root.getFile() makes a trip to the browser process,
-          // but it might be possible avoid that by calling
-          // WebFrame::createFileEntry().
-          fs.root.getFile(baseName, {}, function(fileEntry) {
-            entryIdManager.registerEntry(id, fileEntry);
-            callback(fileEntry);
-          }, function(fileError) {
-            lastError.run('fileSystem.' + functionName,
-                          'Error getting fileEntry, code: ' + fileError.code,
-                          request.stack,
-                          callback);
-          });
-        } catch (e) {
-          lastError.run('fileSystem.' + functionName,
-                        'Error in event handler for onLaunched: ' + e.stack,
-                        request.stack,
-                        callback);
-        }
+        // Loop through the response entries and asynchronously get the
+        // FileEntry for each. We use hasError to ensure that only the first
+        // error is reported. Note that an error can occur either during the
+        // loop or in the asynchronous error callback to getFile.
+        $Array.forEach(response.entries, function(entry) {
+          if (hasError)
+            return;
+          var fileSystemId = entry.fileSystemId;
+          var baseName = entry.baseName;
+          var id = entry.id;
+          var fs = GetIsolatedFileSystem(fileSystemId);
+
+          try {
+            // TODO(koz): fs.root.getFile() makes a trip to the browser process,
+            // but it might be possible avoid that by calling
+            // WebFrame::createFileEntry().
+            fs.root.getFile(baseName, {}, function(fileEntry) {
+              if (hasError)
+                return;
+              entryIdManager.registerEntry(id, fileEntry);
+              entries.push(fileEntry);
+              // Once all entries are ready, pass them to the callback. In the
+              // event of an error, this condition will never be satisfied so
+              // the callback will not be called with any entries.
+              if (entries.length == response.entries.length) {
+                if (response.multiple) {
+                  callback(entries);
+                } else {
+                  callback(entries[0]);
+                }
+              }
+            }, function(fileError) {
+              if (!hasError) {
+                hasError = true;
+                lastError.run(
+                    'fileSystem.' + functionName,
+                    'Error getting fileEntry, code: ' + fileError.code,
+                    request.stack,
+                    callback);
+              }
+            });
+          } catch (e) {
+            if (!hasError) {
+              hasError = true;
+              lastError.run('fileSystem.' + functionName,
+                            'Error getting fileEntry: ' + e.stack,
+                            request.stack,
+                            callback);
+            }
+          }
+        });
       }
     });
   };
   var entryIdManager = require('entryIdManager');
 } else {
   // Force the fileSystem API to be loaded in the background page. Using
   // backgroundPageModuleSystem.require('fileSystem') is insufficient as
   // requireNative is only allowed while lazily loading an API.
   backgroundPage.chrome.fileSystem;
   var bindFileEntryCallback = backgroundPageModuleSystem.require(
@@ skipping 73 matching lines @@
 
   fileSystem.chooseFile = function() {
     console.log("chrome.fileSystem.chooseFile is deprecated");
     console.log("Please use chrome.fileSystem.chooseEntry instead");
     $Function.apply(fileSystem.chooseEntry, this, arguments);
   };
 });
 
 exports.bindFileEntryCallback = bindFileEntryCallback;
 exports.binding = binding.generate();