Add a data source field for volumes.

chrome/browser/chromeos/file_manager/volume_manager.h

Index: chrome/browser/chromeos/file_manager/volume_manager.h
diff --git a/chrome/browser/chromeos/file_manager/volume_manager.h b/chrome/browser/chromeos/file_manager/volume_manager.h
index 54e4d1434ccc65ff4e61c4c7cfe033ef614f0912..860b9e37b70d7a5fa0cd0bcc9e408ac8f5a83094 100644
--- a/chrome/browser/chromeos/file_manager/volume_manager.h
+++ b/chrome/browser/chromeos/file_manager/volume_manager.h
@@ -58,6 +58,14 @@ enum VolumeType {
   NUM_VOLUME_TYPE,
 };
 
+// Source of a volume's data.
+enum VolumeSource {
+  VOLUME_SOURCE_UNKNOWN,
+  VOLUME_SOURCE_FILE,
+  VOLUME_SOURCE_DEVICE,
+  VOLUME_SOURCE_NETWORK
+};
+
 // Says how was the mount performed, whether due to user interaction, or
 // automatic. User interaction includes both hardware (pluggins a USB stick)
 // or software (mounting a ZIP archive) interaction.
@@ -98,6 +106,7 @@ class Volume : public base::SupportsWeakPtr<Volume> {
   const std::string& volume_id() const { return volume_id_; }
   const std::string& file_system_id() const { return file_system_id_; }
   const std::string& extension_id() const { return extension_id_; }
+  const VolumeSource volume_source() const { return volume_source_; }
   VolumeType type() const { return type_; }
   chromeos::DeviceType device_type() const { return device_type_; }
   const base::FilePath& source_path() const { return source_path_; }
@@ -128,6 +137,9 @@ class Volume : public base::SupportsWeakPtr<Volume> {
   // to an empty string.
   std::string extension_id_;
 
+  // The source of the file system's data.
+  VolumeSource volume_source_;
+
   // The type of mounted volume.
   VolumeType type_;