[cros] Added histograms for user image usage

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

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/webui/options/chromeos/change_picture_options_handler.h"
 
 #include "base/callback.h"
+#include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/login/default_user_images.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/options/take_photo_dialog.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/views/window.h"
 #include "chrome/common/chrome_paths.h"
 #include "grit/generated_resources.h"
@@ skipping 126 matching lines @@
   if (!IsDefaultImageUrl(image_url, &user_image_index))
     return;
 
   const SkBitmap* image = ResourceBundle::GetSharedInstance().GetBitmapNamed(
           kDefaultImageResources[user_image_index]);
   UserManager* user_manager = UserManager::Get();
   user_manager->SetLoggedInUserImage(*image);
   user_manager->SaveUserImagePath(
       user_manager->logged_in_user().email(),
       GetDefaultImagePath(user_image_index));
+  UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
+                            user_image_index,
+                            kDefaultImagesCount + 2);

[jar (doing other things), 2011/08/10 17:48:52]

nit suggestion: Since you name and define (the size of) this histogram three
times, it is probably worth factoring it out to a little local static function
that just takes the sample.  Too many folks instigate typos in one of these
definitions, and it is just easier to avoid replicating the macro invocation. 
In addition to readability, it might actually compile a tad smaller (macro
invocation has a few lines of code)... but I'm focusing on readability and
maintainability.

 }
 
 void ChangePictureOptionsHandler::FileSelected(const FilePath& path,
                                                int index,
                                                void* params) {
   UserManager::Get()->LoadLoggedInUserImage(path);
+  UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
+                            kDefaultImagesCount + 1,
+                            kDefaultImagesCount + 2);
 }
 
 void ChangePictureOptionsHandler::OnPhotoAccepted(const SkBitmap& photo) {
   UserManager* user_manager = UserManager::Get();
   DCHECK(user_manager);
 
   const UserManager::User& user = user_manager->logged_in_user();
   DCHECK(!user.email().empty());
 
   user_manager->SetLoggedInUserImage(photo);
   user_manager->SaveUserImage(user.email(), photo);
+  UMA_HISTOGRAM_ENUMERATION("UserImage.ChangeChoice",
+                            kDefaultImagesCount,
+                            kDefaultImagesCount + 2);
 }
 
 gfx::NativeWindow ChangePictureOptionsHandler::GetBrowserWindow() const {
   Browser* browser = BrowserList::FindBrowserWithProfile(web_ui_->GetProfile());
   if (!browser)
     return NULL;
   return browser->window()->GetNativeHandle();
 }
 
 }  // namespace chromeos