Show a local folder's size in QuickView.

ui/file_manager/file_manager/foreground/elements/files_metadata_box.js

Index: ui/file_manager/file_manager/foreground/elements/files_metadata_box.js
diff --git a/ui/file_manager/file_manager/foreground/elements/files_metadata_box.js b/ui/file_manager/file_manager/foreground/elements/files_metadata_box.js
index 9040b37a80b49d94af598ef1971330001db74c06..9bc95b9b2c44ae403cde27744859e803fc10dd3a 100644
--- a/ui/file_manager/file_manager/foreground/elements/files_metadata_box.js
+++ b/ui/file_manager/file_manager/foreground/elements/files_metadata_box.js
@@ -18,6 +18,9 @@ var FilesMetadataBox = Polymer({
     imageHeight: Number,
     mediaTitle: String,
     mediaArtist: String,
+
+    // Whether the value is the middle of loading.
+    loading: Boolean,

[fukino, 2016/09/06 09:12:44]

'loading' sounds like all the properties are loading.
How about using 'laodingSize' or 'isSizeLoading'?

[harukam, 2016/09/06 11:25:24]

Agree. I like 'isSizeLoading' better.

   },
 
   // Clears fields.
@@ -32,6 +35,8 @@ var FilesMetadataBox = Polymer({
     this.imageHeight = 0;
     this.mediaTitle = '';
     this.mediaArtist = '';
+
+    this.loading = false;
   },
 
   /**
@@ -86,4 +91,10 @@ var FilesMetadataBox = Polymer({
     return '';
   },
 
+  /**
+   * @param {boolean} loading
+   */
+  setLoading: function(loading) {

[fukino, 2016/09/06 09:12:44]

You can simply call, for example, 'metadataBox_.loading = true' 

[harukam, 2016/09/06 11:25:24]

Acknowledged.

+    this.loading = loading;
+  },
 });