Re-enable UMA metric WinJumplist.CreateIconFilesCount

chrome/browser/win/jumplist.cc

Index: chrome/browser/win/jumplist.cc
diff --git a/chrome/browser/win/jumplist.cc b/chrome/browser/win/jumplist.cc
index 6dad5579697389d68a137d050de08c7ae6b97199..a3b9b236e93ec289d19b2eb16b143ebbce6bfd0f 100644
--- a/chrome/browser/win/jumplist.cc
+++ b/chrome/browser/win/jumplist.cc
@@ -240,6 +240,9 @@ bool UpdateJumpList(const wchar_t* app_id,
     recently_closed_items = recently_closed_pages.size();
   }
 
+  // Record the amout of icons created per JumpList update.

[grt (UTC plus 2), 2017/04/28 07:17:00]

nit: amount -> number

[chengx, 2017/04/28 18:12:40]

Done.

+  int icons_created = 0;
+
   if (most_visited_pages_have_updates) {
     // Delete the content in JumpListIconsMostVisited folder and log the results
     // to UMA.
@@ -259,6 +262,8 @@ bool UpdateJumpList(const wchar_t* app_id,
       // Create icon files for shortcuts in the "Most Visited" category.
       CreateIconFiles(icon_dir_most_visited, most_visited_pages,
                       most_visited_items);
+
+      icons_created += std::min(most_visited_pages.size(), most_visited_items);

[grt (UTC plus 2), 2017/04/28 07:17:00]

is the intention to report the number of files successfully created? if so,
there are error paths in CreateIconFiles that may result in fewer files being
created than requested. how about making CreateIconFiles return the number of
files it actually created so that the real value can be used directly?

[chengx, 2017/04/28 18:12:40]

Actually, I only care about the number of icons that Chrome requests to create.
The number of icons created may be fewer than that of being requested, which can
be due to various reasons. Some of them are even unrelated to Chrome. What I
focus on is to reduce the request amount.

I have renamed "icons_created" to "icons_to_create", and updated the CL
description to better convey my intention. Sorry about the confusion.

     }
   }
 
@@ -276,10 +281,16 @@ bool UpdateJumpList(const wchar_t* app_id,
       // Create icon files for shortcuts in the "Recently Closed" category.
       CreateIconFiles(icon_dir_recent_closed, recently_closed_pages,
                       recently_closed_items);
+
+      icons_created +=
+          std::min(recently_closed_pages.size(), recently_closed_items);
     }
   }
 
   // TODO(chengx): Remove the UMA histogram after fixing http://crbug.com/40407.
+  UMA_HISTOGRAM_COUNTS_100("WinJumplist.CreateIconFilesCount", icons_created);
+
+  // TODO(chengx): Remove the UMA histogram after fixing http://crbug.com/40407.
   SCOPED_UMA_HISTOGRAM_TIMER("WinJumplist.UpdateJumpListDuration");
 
   // Update the "Most Visited" category of the JumpList if it exists.