[GCM] Add connection/persistent store metric collection

google_apis/gcm/engine/rmq_store.cc

Index: google_apis/gcm/engine/rmq_store.cc
diff --git a/google_apis/gcm/engine/rmq_store.cc b/google_apis/gcm/engine/rmq_store.cc
index 49c6809785974903cfce6a4ede966547a8f02326..894fc868fa0bdb1f15286fcda191340f479da733 100644
--- a/google_apis/gcm/engine/rmq_store.cc
+++ b/google_apis/gcm/engine/rmq_store.cc
@@ -7,9 +7,11 @@
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback.h"
+#include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/metrics/histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
@@ -144,6 +146,7 @@ void RMQStore::Backend::Load(const LoadCallback& callback) {
   leveldb::Status status = leveldb::DB::Open(options,
                                              path_.AsUTF8Unsafe(),
                                              &db);
+  UMA_HISTOGRAM_BOOLEAN("GCM.LoadSucceeded", status.ok());
   if (!status.ok()) {
     LOG(ERROR) << "Failed to open database " << path_.value()
                << ": " << status.ToString();
@@ -170,6 +173,20 @@ void RMQStore::Backend::Load(const LoadCallback& callback) {
     return;
   }
 
+  // Only record histograms if GCM had already been set up for this device.
+  if (result.device_android_id != 0 && result.device_security_token != 0) {
+    int64 file_size = 0;
+    if (base::GetFileSize(path_, &file_size)) {
+      UMA_HISTOGRAM_COUNTS("GCM.StoreSizeKB",
+                           static_cast<int>(file_size / 1024));

[fgorski, 2014/01/02 23:45:40]

That does not make a distinction between a 0 size store and a
1-1023B size store. Would that information be useful at any point?

[Nicolas Zea, 2014/01/02 23:48:21]

A 0 store should not happen if the store has been initialized with an android id
and security token (which we verify above), so I don't think it's useful to
distinguish. And I'm not sure this is an interesting metric for those users who
aren't signed in and therefore don't have GCM initialized.

+    }
+    UMA_HISTOGRAM_COUNTS("GCM.RestoredOutgoingMessages",
+                         result.outgoing_messages.size());
+    UMA_HISTOGRAM_COUNTS("GCM.RestoredIncomingMessages",
+                         result.incoming_messages.size());
+    UMA_HISTOGRAM_COUNTS("GCM.NumUsers", result.user_serial_numbers.size());
+  }
+
   DVLOG(1) << "Succeeded in loading " << result.incoming_messages.size()
           << " unacknowledged incoming messages and "
           << result.outgoing_messages.size()