Don't send machine and user ID to Omaha anymore. Send a/r pings instead.

This avoids sending a unique ID in order to track active user counts.
Note that this CL doesn't remove the machine/user/Omaha ID/file from
the params object -- it just makes them unused/obsolete. Removal will
be done in a subsequent CL in an effort to make this CL smaller.

BUG=1439
TEST=unit tests, x86-generic, arm-generic, gmerged and inspected logs

Review URL: http://codereview.chromium.org/2856070
diff --git a/update_attempter.cc b/update_attempter.cc
index 939e074..50c59ab 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -134,7 +134,8 @@
 
   // Actions:
   shared_ptr<OmahaRequestAction> update_check_action(
-      new OmahaRequestAction(omaha_request_params_,
+      new OmahaRequestAction(prefs_,
+                             omaha_request_params_,
                              NULL,
                              new LibcurlHttpFetcher));
   shared_ptr<OmahaResponseHandlerAction> response_handler_action(
@@ -144,14 +145,16 @@
   shared_ptr<FilesystemCopierAction> kernel_filesystem_copier_action(
       new FilesystemCopierAction(true));
   shared_ptr<OmahaRequestAction> download_started_action(
-      new OmahaRequestAction(omaha_request_params_,
+      new OmahaRequestAction(prefs_,
+                             omaha_request_params_,
                              new OmahaEvent(
                                  OmahaEvent::kTypeUpdateDownloadStarted),
                              new LibcurlHttpFetcher));
   shared_ptr<DownloadAction> download_action(
       new DownloadAction(new LibcurlHttpFetcher));
   shared_ptr<OmahaRequestAction> download_finished_action(
-      new OmahaRequestAction(omaha_request_params_,
+      new OmahaRequestAction(prefs_,
+                             omaha_request_params_,
                              new OmahaEvent(
                                  OmahaEvent::kTypeUpdateDownloadFinished),
                              new LibcurlHttpFetcher));
@@ -162,7 +165,8 @@
   shared_ptr<PostinstallRunnerAction> postinstall_runner_action_postcommit(
       new PostinstallRunnerAction(false));
   shared_ptr<OmahaRequestAction> update_complete_action(
-      new OmahaRequestAction(omaha_request_params_,
+      new OmahaRequestAction(prefs_,
+                             omaha_request_params_,
                              new OmahaEvent(OmahaEvent::kTypeUpdateComplete),
                              new LibcurlHttpFetcher));
 
@@ -389,7 +393,8 @@
     return false;
 
   shared_ptr<OmahaRequestAction> error_event_action(
-      new OmahaRequestAction(omaha_request_params_,
+      new OmahaRequestAction(prefs_,
+                             omaha_request_params_,
                              error_event_.release(),  // Pass ownership.
                              new LibcurlHttpFetcher));
   actions_.push_back(shared_ptr<AbstractAction>(error_event_action));