Add histgrams to Folder shortcut feature in Files.app.

BUG=none
TEST=Files.app runs, the volume list on the left works.
R=asvitkine@chromium.org, mtomasz@chromium.org

Review URL: https://codereview.chromium.org/22634008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@217148 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/file_manager/js/folder_shortcuts_data_model.js

@@ -35,6 +35,9 @@ function FolderShortcutsDataModel() {
     if (list instanceof Array) {
       list = filter(list);
 
+      // Record metrics.
+      metrics.recordSmallCount('FolderShortcut.Count', list.length);
+
       var permutation = this.calculatePermitation_(this.array_, list);
       this.array_ = list;
       this.firePermutedEvent_(permutation);
@@ -160,6 +163,7 @@ FolderShortcutsDataModel.prototype = {
     this.firePermutedEvent_(
         this.calculatePermitation_(oldArray, this.array_));
     this.save_();
+    metrics.recordUserAction('FolderShortcut.Add');
     return addedIndex;
   },
 
@@ -184,6 +188,7 @@ FolderShortcutsDataModel.prototype = {
       this.firePermutedEvent_(
           this.calculatePermitation_(oldArray, this.array_));
       this.save_();
+      metrics.recordUserAction('FolderShortcut.Remove');
       return removedIndex;
     }
 

chrome/browser/resources/file_manager/js/navigation_list.js

@@ -316,8 +316,10 @@ NavigationList.prototype.renderRoot_ = function(path) {
   item.setPath(path);
 
   var handleClick = function() {
-    if (item.selected && path !== this.directoryModel_.getCurrentDirPath())
+    if (item.selected && path !== this.directoryModel_.getCurrentDirPath()) {
+      metrics.recordUserAction('FolderShortcut.Navigate');
       this.changeDirectory_(path);
+    }
   }.bind(this);
   item.addEventListener('click', handleClick);
 
@@ -371,6 +373,7 @@ NavigationList.prototype.setContextMenu = function(menu) {
 
 /**
  * Selects the n-th item from the list.
+ *
  * @param {number} index Item index.
  * @return {boolean} True for success, otherwise false.
  */
@@ -383,9 +386,12 @@ NavigationList.prototype.selectByIndex = function(index) {
     return false;
 
   // Prevents double-moving to the current directory.
+  // eg. When user clicks the item, changing directory has already been done in
+  //     click handler.
   if (this.directoryModel_.getCurrentDirEntry().fullPath == newPath)
     return false;
 
+  metrics.recordUserAction('FolderShortcut.Navigate');
   this.changeDirectory_(newPath);
   return true;
 };

tools/metrics/histograms/histograms.xml

@@ -3885,6 +3885,34 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="FileBrowser.FolderShortcut.Add">
+  <summary>
+    Chrome OS File Browser: this is recorded when the user adds a folder
+    shortcut.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.FolderShortcut.Count">
+  <summary>
+    Chrome OS File Browser: number of saved folder shorcuts. This is recorded
+    when Files.app is launched.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.FolderShortcut.Navigate">
+  <summary>
+    Chrome OS File Browser: this is recorded when the user clicks or selects a
+    folder shortcut and is navigated to the target folder.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.FolderShortcut.Remove">
+  <summary>
+    Chrome OS File Browser: this is recorded when the user removes a folder
+    shortcut.
+  </summary>
+</histogram>
+
 <histogram name="FileBrowser.Load" units="milliseconds">
   <summary>
     Chrome OS File Browser is an built-in extension without a background page.