Make UMA_HISTOGRAM_ENUMERATION work with scoped enums.

chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc

Index: chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc
diff --git a/chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc
index d1796b121325d7b2f7d146b0c00553fa424c065e..e5661d299db19e356a83355987f2894083ce1303 100644
--- a/chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.cc
@@ -352,16 +352,16 @@ void ChangePictureOptionsHandler::HandleSelectImage(
         user_manager::UserImage::CreateAndEncode(
             previous_image_, user_manager::UserImage::FORMAT_JPEG));
 
-    UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
-                              default_user_image::kHistogramImageOld,
-                              default_user_image::kHistogramImagesCount);
+    UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",

[wychen, 2017/03/27 19:44:01]

Do you know why these default_user_image:: constants have to be in "extern const
int" instead of simply "const int"? Avoid recompilation and binary bloat? Maybe
they can be converted to enum as well.

[dcheng, 2017/03/28 07:16:45]

This "enum" has a pretty weird structure, so I opted not to touch it. If someone
from CrOS wants to fix it, they can =P

(See
https://cs.chromium.org/chromium/src/chrome/browser/chromeos/login/users/defa...:
the gap at the beginning of the constants is intentional. Since it's sort of an
enum and sort of not, I'm opting to just leave it alone)

+                               default_user_image::kHistogramImageOld,
+                               default_user_image::kHistogramImagesCount);
     VLOG(1) << "Selected old user image";
   } else if (image_type == "default" &&
              default_user_image::IsDefaultImageUrl(image_url, &image_index)) {
     // One of the default user images.
     user_image_manager->SaveUserDefaultImageIndex(image_index);
 
-    UMA_HISTOGRAM_ENUMERATION(
+    UMA_HISTOGRAM_EXACT_LINEAR(
         "UserImage.ChangeChoice",
         default_user_image::GetDefaultImageHistogramValue(image_index),
         default_user_image::kHistogramImagesCount);
@@ -379,14 +379,14 @@ void ChangePictureOptionsHandler::HandleSelectImage(
     user_image_manager->SaveUserImageFromProfileImage();
 
     if (previous_image_index_ == user_manager::User::USER_IMAGE_PROFILE) {
-      UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
-                                default_user_image::kHistogramImageOld,
-                                default_user_image::kHistogramImagesCount);
+      UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",
+                                 default_user_image::kHistogramImageOld,
+                                 default_user_image::kHistogramImagesCount);
       VLOG(1) << "Selected old (profile) user image";
     } else {
-      UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
-                                default_user_image::kHistogramImageFromProfile,
-                                default_user_image::kHistogramImagesCount);
+      UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",
+                                 default_user_image::kHistogramImageFromProfile,
+                                 default_user_image::kHistogramImagesCount);
       VLOG(1) << "Selected profile image";
     }
   } else {
@@ -404,9 +404,9 @@ void ChangePictureOptionsHandler::FileSelected(const base::FilePath& path,
   ChromeUserManager::Get()
       ->GetUserImageManager(GetUser()->GetAccountId())
       ->SaveUserImageFromFile(path);
-  UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
-                            default_user_image::kHistogramImageFromFile,
-                            default_user_image::kHistogramImagesCount);
+  UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",
+                             default_user_image::kHistogramImageFromFile,
+                             default_user_image::kHistogramImagesCount);
   VLOG(1) << "Selected image from file";
 }
 
@@ -416,9 +416,9 @@ void ChangePictureOptionsHandler::SetImageFromCamera(
       ->GetUserImageManager(GetUser()->GetAccountId())
       ->SaveUserImage(user_manager::UserImage::CreateAndEncode(
           photo, user_manager::UserImage::FORMAT_JPEG));
-  UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
-                            default_user_image::kHistogramImageFromCamera,
-                            default_user_image::kHistogramImagesCount);
+  UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",
+                             default_user_image::kHistogramImageFromCamera,
+                             default_user_image::kHistogramImagesCount);
   VLOG(1) << "Selected camera photo";
 }