Move content deduplication into the scan process.

ui/file_manager/file_manager/background/js/media_scanner_unittest.js

 // Copyright 2014 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.
 
 /**
  * Stub out the metrics package.
  * @type {!Object.<!string, !Function>}
  */
 var metrics = {
   recordTime: function() {},
   recordValue: function() {}
 };
 
 /** @type {!importer.DefaultMediaScanner} */
 var scanner;
 
 /** @type {!importer.TestImportHistory} */
 var importHistory;
 
 /** @type {!importer.TestDirectoryWatcher} */
 var watcher;
 
+/**
+ * @type {function(!FileEntry, !importer.Destination):
+ *     !Promise<!importer.Disposition>}
+ */
+var dispositionChecker;
+
 // Set up the test components.
 function setUp() {
 
+
   importHistory = new importer.TestImportHistory();
+  // This is the default disposition checker.
+  // Tests can replace this at runtime if they
+  // want specialized behaviors.
+  dispositionChecker = function() {
+    return Promise.resolve(importer.Disposition.ORIGINAL);
+  };
+
   scanner = new importer.DefaultMediaScanner(
       /** @param {!FileEntry} entry */
       function(entry) {
         return Promise.resolve(entry.name);
       },
-      importHistory,
+      function(entry, destination) {
+        return dispositionChecker(entry, destination);
+      },
       function(callback) {
         watcher = new TestDirectoryWatcher(callback);
         return watcher;
       });
 }
 
 /**
  * Verifies that scanning an empty filesystem produces an empty list.
  */
 function testEmptySourceList() {
@@ skipping 110 matching lines @@
 }
 
 /**
  * Verifies that scanning ignores previously imported entries.
  */
 function testIgnoresPreviousImports(callback) {
   importHistory.importedPaths[
       '/testIgnoresPreviousImports/oldimage1234.jpg'] =
           [importer.Destination.GOOGLE_DRIVE];
   var filenames = [
-    'oldimage1234.jpg',
+    'oldimage1234.jpg',    // a history duplicate
+    'driveimage1234.jpg',  // a content duplicate
     'foo.jpg',
     'bar.gif',
     'baz.avi'
   ];
+
+  // Replace the default dispositionChecker with a function
+  // that treats our dupes accordingly.
+  dispositionChecker = function(entry, destination) {
+    if (entry.name === filenames[0]) {
+      return Promise.resolve(importer.Disposition.HISTORY_DUPLICATE);
+    }
+    if (entry.name === filenames[1]) {
+      return Promise.resolve(importer.Disposition.CONTENT_DUPLICATE);
+    }
+    return Promise.resolve(importer.Disposition.ORIGINAL);
+  };
+
   var expectedFiles = [
     '/testIgnoresPreviousImports/foo.jpg',
     '/testIgnoresPreviousImports/bar.gif',
     '/testIgnoresPreviousImports/baz.avi'
   ];
   reportPromise(
       makeTestFileSystemRoot('testIgnoresPreviousImports')
           .then(populateDir.bind(null, filenames))
           .then(
               /**
@@ skipping 85 matching lines @@
                 return Promise.all(['foo.0', 'foo.1'].map(
                     getDirectory.bind(null, root))).then(
                         function(directories) {
                           return scanner.scan(directories).whenFinal();
                         });
               })
           .then(assertResults.bind(null, expectedFiles)),
       callback);
 }
 
-function testDedupesFiles(callback) {
+function testDedupesFilesInScanResult(callback) {
   var filenames = [
     [
       'a',
       'foo.jpg',
       'bar.jpg'
     ],
     [
       'b',
       'foo.jpg',
       'bar.jpg',
@@ skipping 124 matching lines @@
               return new Promise(
                   function(resolve, reject) {
                     dir.getFile(filename, {create: true}, resolve, reject);
                   });
             }
           })).then(
               function() {
                 return dir;
               });
 }