leveldb: Moved to LevelDBEnv.IOError.BFE histogram entries.

third_party/leveldatabase/env_chromium.cc

Index: third_party/leveldatabase/env_chromium.cc
diff --git a/third_party/leveldatabase/env_chromium.cc b/third_party/leveldatabase/env_chromium.cc
index a12edf486182b04c2d58490300a67a9d72c541f0..6aa55ce9fdadba85e9c6d3849454d4cac250ebd2 100644
--- a/third_party/leveldatabase/env_chromium.cc
+++ b/third_party/leveldatabase/env_chromium.cc
@@ -16,6 +16,7 @@
 #include "base/metrics/histogram.h"
 #include "base/process/process_metrics.h"
 #include "base/stl_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/leveldatabase/chromium_logger.h"
 #include "third_party/re2/re2/re2.h"
@@ -326,6 +327,7 @@ class IDBEnv : public ChromiumEnv {
  public:
   IDBEnv() : ChromiumEnv() {
     name_ = "LevelDBEnv.IDB";
+    uma_ioerror_base_name_ = name_ + ".IOError.PFE";
     make_backup_ = true;
   }
 };
@@ -529,6 +531,7 @@ ChromiumEnv::ChromiumEnv()
       bgsignal_(&mu_),
       started_bgthread_(false),
       kMaxRetryTimeMillis(1000) {
+  uma_ioerror_base_name_ = name_ + ".IOError.PFE";

[dgrogan, 2015/01/21 01:47:56]

maybe use bFE to indicate base::File::Error instead of the old name
PlatformFileError?

[cmumford, 2015/02/13 22:15:52]

I started with that originally, but eventually got up into histograms.xml where
I specified the enum to be PlatformFileError - which as you mentioned is really
no longer. I felt it was better to be consistently wrong with the name. I'll
change it to "BFE" and let's see how it looks.

 }
 
 ChromiumEnv::~ChromiumEnv() {
@@ -931,18 +934,17 @@ void ChromiumEnv::RecordBackupResult(bool result) const {
 
 base::HistogramBase* ChromiumEnv::GetOSErrorHistogram(MethodID method,
                                                       int limit) const {
-  std::string uma_name(name_);
-  // TODO(dgrogan): This is probably not the best way to concatenate strings.
-  uma_name.append(".IOError.").append(MethodIDToString(method));
+  std::string uma_name;
+  base::StringAppendF(&uma_name, "%s.%s", uma_ioerror_base_name_.c_str(),
+                      MethodIDToString(method));
   return base::LinearHistogram::FactoryGet(uma_name, 1, limit, limit + 1,
       base::Histogram::kUmaTargetedHistogramFlag);
 }
 
 base::HistogramBase* ChromiumEnv::GetMethodIOErrorHistogram() const {
-  std::string uma_name(name_);
-  uma_name.append(".IOError");
-  return base::LinearHistogram::FactoryGet(uma_name, 1, kNumEntries,
-      kNumEntries + 1, base::Histogram::kUmaTargetedHistogramFlag);
+  return base::LinearHistogram::FactoryGet(
+      uma_ioerror_base_name_, 1, kNumEntries, kNumEntries + 1,
+      base::Histogram::kUmaTargetedHistogramFlag);
 }
 
 base::HistogramBase* ChromiumEnv::GetMaxFDHistogram(