Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/memory/memory_metrics.cc

Index: ios/chrome/browser/memory/memory_metrics.cc
diff --git a/ios/chrome/browser/memory/memory_metrics.cc b/ios/chrome/browser/memory/memory_metrics.cc
index 1de2e2a451cd5ba666538818c7387212dd551ee2..43bf68740c5200f00efe6394dbf3c205ff344495 100644
--- a/ios/chrome/browser/memory/memory_metrics.cc
+++ b/ios/chrome/browser/memory/memory_metrics.cc
@@ -8,9 +8,10 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include <memory>
+
 #include "base/logging.h"
 #include "base/mac/scoped_mach_port.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/process/process_handle.h"
 #include "base/process/process_metrics.h"
 #include "build/build_config.h"
@@ -47,7 +48,7 @@ uint64_t GetFreePhysicalBytes() {
 
 uint64_t GetRealMemoryUsedInBytes() {
   base::ProcessHandle process_handle = base::GetCurrentProcessHandle();
-  scoped_ptr<base::ProcessMetrics> process_metrics(
+  std::unique_ptr<base::ProcessMetrics> process_metrics(
       base::ProcessMetrics::CreateProcessMetrics(process_handle));
   return static_cast<uint64_t>(process_metrics->GetWorkingSetSize());
 }