Move malloc/partition_alloc memory usage functions to base

base/process/process_metrics_posix.cc

Index: base/process/process_metrics_posix.cc
diff --git a/base/process/process_metrics_posix.cc b/base/process/process_metrics_posix.cc
index a4445e8bc2e80ff6fdac1e04074224298ba422ca..677e26d12148d084f21a2906837e939f82be4664 100644
--- a/base/process/process_metrics_posix.cc
+++ b/base/process/process_metrics_posix.cc
@@ -14,6 +14,12 @@
 #include "base/logging.h"
 #include "build/build_config.h"
 
+#if defined(OS_MACOSX)
+#include <malloc/malloc.h>
+#else
+#include <malloc.h>
+#endif
+
 namespace base {
 
 int64_t TimeValToMicroseconds(const struct timeval& tv) {
@@ -83,4 +89,19 @@ size_t GetPageSize() {
   return getpagesize();
 }
 
+size_t ProcessMetrics::GetMallocUsage() {
+#if defined(OS_MACOSX) || defined(OS_IOS)
+  malloc_statistics_t stats = {0};
+  malloc_zone_statistics(nullptr, &stats);
+  return stats.size_in_use;
+#elif defined(OS_LINUX) || defined(OS_ANDROID)
+  struct mallinfo minfo = mallinfo();
+#if defined(USE_TCMALLOC)
+  return minfo.uordblks;
+#else
+  return minfo.hblkhd + minfo.arena;
+#endif
+#endif
+}
+
 }  // namespace base