Refactoring: Use const-refs

content/browser/memory/memory_condition_observer.cc

 // Copyright 2016 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 "content/browser/memory/memory_condition_observer.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "components/variations/variations_associated_data.h"
 #include "content/browser/memory/memory_monitor.h"
 
 namespace content {
 
 namespace {
 
-// A expected renderer size. These values come from the median of appropriate
+// An expected renderer size. These values come from the median of appropriate
 // UMA stats.
 #if defined(OS_ANDROID) || defined(OS_IOS)
 const int kDefaultExpectedRendererSizeMB = 40;
 #elif defined(OS_WIN)
 const int kDefaultExpectedRendererSizeMB = 70;
 #else  // Mac, Linux, and ChromeOS
 const int kDefaultExpectedRendererSizeMB = 120;
 #endif
 
 // Default values for parameters to determine the global state.
 const int kDefaultNewRenderersUntilWarning = 4;
 const int kDefaultNewRenderersUntilCritical = 2;
 const int kDefaultNewRenderersBackToNormal = 5;
 const int kDefaultNewRenderersBackToWarning = 3;
 const int kDefaultMonitoringIntervalSeconds = 1;
 const int kMonitoringIntervalBackgroundedSeconds = 120;
 
-void SetIntVariationParameter(const std::map<std::string, std::string> params,
+void SetIntVariationParameter(const std::map<std::string, std::string>& params,
                               const char* name,
                               int* target) {
   const auto& iter = params.find(name);
   if (iter == params.end())
     return;
   int value;
   if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
     DCHECK(value > 0);
     *target = value;
   }
 }
 
 void SetSecondsVariationParameter(
-    const std::map<std::string, std::string> params,
+    const std::map<std::string, std::string>& params,
     const char* name,
     base::TimeDelta* target) {
   const auto& iter = params.find(name);
   if (iter == params.end())
     return;
   int value;
   if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
     DCHECK(value > 0);
     *target = base::TimeDelta::FromSeconds(value);
   }
@@ skipping 116 matching lines @@
 }
 
 bool MemoryConditionObserver::ValidateParameters() {
   return (new_renderers_until_warning_ > new_renderers_until_critical_) &&
          (new_renderers_back_to_normal_ > new_renderers_back_to_warning_) &&
          (new_renderers_back_to_normal_ > new_renderers_until_warning_) &&
          (new_renderers_back_to_warning_ > new_renderers_until_critical_);
 }
 
 }  // namespace content