Add detailed performance histograms to Files.app. (Abandoned)

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index f0c5161e109af3a2c12fd04d7c62fa465c97b961..9e1aafb1dbc8266bcdcb98b98348b5de86607408 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -3894,6 +3894,54 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="FileBrowser.Load.AdditionalUI" units="milliseconds">
+  <summary>
+    Time to load additional UI elements during initialization of Files app. This
+    step loads all other UI elements, which do not require access to the file
+    system.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.Display" units="milliseconds">
+  <summary>
+    Time to display the most basic UI of Files.app (without the file list
+    loaded).
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.EssentialUI" units="milliseconds">
+  <summary>
+    Time to load essential UI elements during initialization of Files app. This
+    step loads only these UI elements required to display the most basic UI.
+    File system is not yet available, nor any other heavy elements.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.FileSystemUI" units="milliseconds">
+  <summary>
+    Time to load file system related UI elements during initialization of Files
+    app. Only in this UI initialization step, it can be assumed that file system
+    is already available.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.General" units="milliseconds">
+  <summary>
+    Time to load essential data used by other steps of the initialization of
+    Files app.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.Preference" units="milliseconds">
+  <summary>
+    Time to load preferences during initialization of Files app.
+  </summary>
+</histogram>
+
+<histogram name="FileBrowser.Load.Strings" units="milliseconds">
+  <summary>Time to load strings during initialization of Files app.</summary>
+</histogram>
+
 <histogram name="FileBrowser.OpeningFileType" enum="FileType">
   <obsolete>
     Deprecated 4/2013, and replaced by FileBrowser.ViewingFileType.