[chrome.dial] Adds chrome.dial.fetchDeviceDecription API.

chrome/browser/extensions/api/dial/dial_device_data.cc

Index: chrome/browser/extensions/api/dial/dial_device_data.cc
diff --git a/chrome/browser/extensions/api/dial/dial_device_data.cc b/chrome/browser/extensions/api/dial/dial_device_data.cc
index 821f0553e900c0272f67b7b15d1178a66a7353d3..4950d4afa9178c887cb5b33c6d4752a8f575fcb2 100644
--- a/chrome/browser/extensions/api/dial/dial_device_data.cc
+++ b/chrome/browser/extensions/api/dial/dial_device_data.cc
@@ -55,4 +55,9 @@ void DialDeviceData::FillDialDevice(api::dial::DialDevice* device) const {
     device->config_id.reset(new int(config_id_));
 }
 
+DialDeviceDescription::DialDeviceDescription(
+    const std::string& device_description,
+    const GURL& app_url)
+    : device_description(device_description), app_url(app_url) {}
+
 }  // namespace extensions