Domain Reliability: Add rudimentary WebUI page.

components/domain_reliability/context.h

Index: components/domain_reliability/context.h
diff --git a/components/domain_reliability/context.h b/components/domain_reliability/context.h
index 098e4fc2802659c076f4cbcd331d90e9252d672e..e1fe71f4ae8320a7b23fca8a8e9ea5a3a58da2db 100644
--- a/components/domain_reliability/context.h
+++ b/components/domain_reliability/context.h
@@ -17,6 +17,10 @@
 
 class GURL;
 
+namespace base {
+class Value;
+}
+
 namespace domain_reliability {
 
 struct DomainReliabilityBeacon;
@@ -45,6 +49,10 @@ class DOMAIN_RELIABILITY_EXPORT DomainReliabilityContext {
   // Called to clear browsing data, since beacons are like browsing history.
   void ClearBeacons();
 
+  // Gets a Value containing data that can be formatted into a web page for
+  // debugging purposes.
+  scoped_ptr<base::Value> GetWebUIData() const;
+
   void GetQueuedDataForTesting(
       size_t resource_index,
       std::vector<DomainReliabilityBeacon>* beacons_out,