[Sync] Fixing easy lint violations.

components/sync/syncable/directory_backing_store.cc

 // Copyright 2012 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 "components/sync/syncable/directory_backing_store.h"
 
 #include <stddef.h>
 
 #include <limits>
 #include <unordered_set>
+#include <utility>
 
 #include "base/base64.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
@@ skipping 207 matching lines @@
 bool SaveEntryToDB(sql::Statement* save_statement, const EntryKernel& entry) {
   save_statement->Reset(true);
   BindFields(entry, save_statement);
   return save_statement->Run();
 }
 
 // total_specifics_copies : Total copies of entries in memory, include extra
 // copy for some entries which create by copy-on-write mechanism.
 // entries_counts : entry counts for each model type.
 void UploadModelTypeEntryCount(const int total_specifics_copies,
-                               const int(&entries_counts)[MODEL_TYPE_COUNT]) {

[maxbogue, 2016/10/04 00:11:51]

Wat. Was this previously accepting a reference to the array? Wouldn't you be
copying the array now? The parens don't seem necessary though...

[skym, 2016/10/04 15:57:35]

Whoops, okay after Googling to try to better explain to you why this is safe, it
turns out it is not, reverting.

So, I looked up yesterday how to pass an array by reference, and it seemed that
arrays were always passed by reference, so I was like, great, lets remove this
funky syntax.

Googling again though
http://stackoverflow.com/questions/5724171/passing-an-array-by-reference/5724...
, it looks like the size gets ignored with the syntax I moved to. So back to the
original.

However, it seems if I just add a space between "int" and "(&entries_count)" we
dodge the lint complaint. Yay!

[maxbogue, 2016/10/04 16:24:45]

Ah, cool!

+                               const int entries_counts[MODEL_TYPE_COUNT]) {
   int total_entry_counts = 0;
   for (int i = FIRST_REAL_MODEL_TYPE; i < MODEL_TYPE_COUNT; ++i) {
     std::string model_type;
     if (RealModelTypeToNotificationType((ModelType)i, &model_type)) {
       std::string full_histogram_name = "Sync.ModelTypeCount." + model_type;
       base::HistogramBase* histogram = base::Histogram::FactoryGet(
           full_histogram_name, 1, 1000000, 50,
           base::HistogramBase::kUmaTargetedHistogramFlag);
       if (histogram)
         histogram->Add(entries_counts[i]);
@@ skipping 1512 matching lines @@
   DCHECK(CalledOnValidThread());
   DCHECK(!catastrophic_error_handler.is_null());
   catastrophic_error_handler_ = catastrophic_error_handler;
   sql::Connection::ErrorCallback error_callback =
       base::Bind(&OnSqliteError, catastrophic_error_handler_);
   db_->set_error_callback(error_callback);
 }
 
 }  // namespace syncable
 }  // namespace syncer