Move GetUdevDevicePropertyValue from components/storage_monitor to device/udev_linux and rename to UdevDeviceGetPropertyValue

I am going to use this as part of Web MIDI and don't want to depend on storage_monitor.

Review URL: https://codereview.chromium.org/982883004

Cr-Commit-Position: refs/heads/master@{#319415}

2 files changed, 13 insertions, 0 deletions

diff --git a/device/udev_linux/udev.cc b/device/udev_linux/udev.cc
index ae23bef..a3fc0e9 100644
--- a/device/udev_linux/udev.cc
+++ b/device/udev_linux/udev.cc
@@ -146,4 +146,10 @@ void udev_unref(udev* udev) {
   UdevLoader::Get()->udev_unref(udev);
 }
 
+std::string UdevDeviceGetPropertyValue(udev_device* udev_device,
+                                       const char* key) {
+  const char* value = device::udev_device_get_property_value(udev_device, key);
+  return value ? value : std::string();
+}
+
 }  // namespace device
diff --git a/device/udev_linux/udev.h b/device/udev_linux/udev.h
index 2bb8df2..3039aa2 100644
--- a/device/udev_linux/udev.h
+++ b/device/udev_linux/udev.h
@@ -9,6 +9,8 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#include <string>
+
 #if !defined(USE_UDEV)
 #error "USE_UDEV not defined"
 #endif
@@ -72,6 +74,11 @@ void udev_set_log_fn(
 void udev_set_log_priority(struct udev* udev, int priority);
 void udev_unref(udev* udev);
 
+// Calls udev_device_get_property_value() and replaces missing values with
+// the empty string.
+std::string UdevDeviceGetPropertyValue(udev_device* udev_device,
+                                       const char* key);
+
 }  // namespace device
 
 #endif  // DEVICE_UDEV_LINUX_UDEV_H_