[SystemInfo API] Rewrite storage info provider using storage monitor impl

chrome/browser/storage_monitor/storage_monitor_mac.mm

Index: chrome/browser/storage_monitor/storage_monitor_mac.mm
diff --git a/chrome/browser/storage_monitor/storage_monitor_mac.mm b/chrome/browser/storage_monitor/storage_monitor_mac.mm
index 266f6114a0199a4ceb97fd0cab34d4fdeec7cb7b..93292143922696fcec5cf4a38cabec7cc245ce7c 100644
--- a/chrome/browser/storage_monitor/storage_monitor_mac.mm
+++ b/chrome/browser/storage_monitor/storage_monitor_mac.mm
@@ -310,6 +310,16 @@ void StorageMonitorMac::EjectDevice(
                                    base::Bind(EjectDisk, options));
 }
 
+std::vector<StorageInfo> StorageMonitorMac::GetAllAvailableStorages() const {
+  std::vector<StorageInfo> results;
+
+  std::map<std::string, StorageInfo>::const_iterator it;
+  for (it = disk_info_map_.begin(); it != disk_info_map_.end(); ++it)
+    results.push_back(it->second);
+
+  return results;
+}
+
 // static
 void StorageMonitorMac::DiskAppearedCallback(DADiskRef disk, void* context) {
   StorageMonitorMac* monitor = static_cast<StorageMonitorMac*>(context);