Create zip file in temporary storage.

This will avoid exposing in-progress zip file to the destination folder.
It will resolve the issues like:
- the zip file is synced to Drive with incomplete state, having multiple
  revisions
- when cancelling zip packing, the file appears in the trash of Drive

Bug: 714579,785096,785093,785086,797873
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I0b32515d5e896d87e1dee499f1eea40dd7a481f0
Reviewed-on: https://chromium-review.googlesource.com/844442
Commit-Queue: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547428}

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

@@ -880,4 +880,55 @@ unpacker.app = {
     else
       unpacker.app.onLaunchedWithUnpack(launchData, opt_onSuccess, opt_onError);
   },
+
+  /**
+   * Clean all temporary files inside the work directory.
+   * Those files are usually moved to the destination directory when finished
+   * or removed when any error happened, but might be left there when the
+   * extension was aborted by runtime errors or system shutdown.
+   */
+  cleanWorkDirectory: function() {
+    return new Promise(
+               webkitRequestFileSystem.bind(null, TEMPORARY, 0 /* size */))
+        .then((fs) => new Promise(function(resolve, reject) {
+                const reader = fs.root.createReader();
+                let allEntries = [];
+                function scanEntries() {
+                  reader.readEntries((entries) => {
+                    if (entries.length == 0) {
+                      resolve(allEntries);
+                      return;
+                    }
+                    Array.prototype.push.apply(allEntries, entries);
+                    scanEntries();
+                  });
+                }
+                scanEntries();
+              }))
+        .then((allEntries) => {
+          allEntries.forEach((entry) => {
+            if (entry.isDirectory) {
+              entry.removeRecursively(
+                  function() {
+                    console.info(
+                        'Found directory. ',
+                        'Perhaps the extension had exited abnormally.', entry);
+                  },
+                  function() {
+                    console.error('Failed to remove a directory:', entry);
+                  });
+            } else {
+              entry.remove(
+                  function() {
+                    console.info(
+                        'Found a temporary file. ',
+                        'Perhaps the extension had exited abnormally.', entry);
+                  },
+                  function() {
+                    console.error('Failed to remove a temporary file:', entry);
+                  });
+            }
+          });
+        });
+  }
 };

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

@@ -30,3 +30,7 @@ unpacker.app.loadNaclModule('module.nmf', 'application/x-pnacl');
 
 // Load translations
 unpacker.app.loadStringData();
+
+// Clean all temporary files inside the work directory, just in case the
+// extension aborted previously without removing ones.
+unpacker.app.cleanWorkDirectory();

chrome/browser/resources/chromeos/zip_archiver/manifest.json

@@ -23,7 +23,7 @@
       ]
     },
     "notifications",
-    "storage"
+    "unlimitedStorage"
   ],
   "file_system_provider_capabilities": {
     "multipleMounts": true,