FilesApp: Correct MIME types for openxmlformats

Commit https://codereview.chromium.org/1158923004 updated
incorrect escapes in some RegExp constructors, but some
of the escapes were superfluous. When checking the formats
it became obvious that the original MIME types used were
incorrect for the family of openxmlformats documents.
This change corrects the MIME types and removes the
unneeded escapes.

BUG=chromium:675506
TEST=Ran all the FilesApp tests
Signed-off-by: Alex Danilo <adanilo@chromium.org>
Change-Id: Ic79e4655ebb61ea2e7c8fbb83509f899d7d1cb60
Reviewed-on: https://chromium-review.googlesource.com/c/1297775Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602525}

ui/file_manager/file_manager/common/js/file_type.js

@@ -372,8 +372,9 @@ FileType.types = [
     subtype: 'Word',
     pattern: /\.(doc|docx)$/i,
     mimePattern: new RegExp(
-        '/application\\/(msword|vnd\\.openxmlformats\\-' +
-        'officedocument\\./wordprocessingml\\.document)/i')
+        'application/(msword|vnd\\.' +
+            'openxmlformats-officedocument\\.wordprocessingml\\.document)',
+        'i')
   },
   {
     type: 'document',
@@ -382,8 +383,9 @@ FileType.types = [
     subtype: 'PPT',
     pattern: /\.(ppt|pptx)$/i,
     mimePattern: new RegExp(
-        '/application\\/(vnd\\.ms-powerpoint|\\.' +
-        'openxmlformats\\-/officedocument\\.wordprocessingml\\.presentation)/i')
+        'application/vnd\\.(ms-powerpoint|' +
+            'openxmlformats-officedocument\\.presentationml\\.presentation)',
+        'i')
   },
   {
     type: 'document',
@@ -392,8 +394,9 @@ FileType.types = [
     subtype: 'Excel',
     pattern: /\.(xls|xlsx)$/i,
     mimePattern: new RegExp(
-        '/application\\/(vnd\\.ms-excel|\\.' +
-        'openxmlformats\\-/officedocument\\.wordprocessingml\\.sheet)/i')
+        'application/vnd\\.(ms-excel|' +
+            'openxmlformats-officedocument\\.spreadsheetml\\.sheet)',
+        'i')
   }
 ];