Fix missing symbols for pre-linking of the Cast sender library for iOS.

base/process/process_metrics_ios.cc

Index: base/process/process_metrics_ios.cc
diff --git a/base/process/process_metrics_ios.cc b/base/process/process_metrics_ios.cc
index 9ae838d39a0b4ec341c36a52a32accd7a78c7ec1..07f2c8de1d46ff41ed88214b0ac624f94f5eb0d9 100644
--- a/base/process/process_metrics_ios.cc
+++ b/base/process/process_metrics_ios.cc
@@ -6,6 +6,8 @@
 
 #include <mach/task.h>
 
+#include "base/logging.h"
+
 namespace base {
 
 namespace {
@@ -30,6 +32,11 @@ ProcessMetrics* ProcessMetrics::CreateProcessMetrics(ProcessHandle process) {
   return new ProcessMetrics(process);
 }
 
+double ProcessMetrics::GetCPUUsage() {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
 size_t ProcessMetrics::GetPagefileUsage() const {
   task_basic_info_64 task_info_data;
   if (!GetTaskInfo(&task_info_data))
@@ -69,4 +76,10 @@ size_t GetPageSize() {
   return getpagesize();
 }
 
+// Bytes committed by the system.
+size_t GetSystemCommitCharge() {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
 }  // namespace base