Add UMA to track the number of live URLRequests.

net/url_request/url_request_context.h

Index: net/url_request/url_request_context.h
diff --git a/net/url_request/url_request_context.h b/net/url_request/url_request_context.h
index d34c2fdb3bb59c3396b32c99f8e990ce219f6b6f..8c7031018195ae10c74d9a71c0f2b161096dc974 100644
--- a/net/url_request/url_request_context.h
+++ b/net/url_request/url_request_context.h
@@ -225,6 +225,10 @@ class NET_EXPORT URLRequestContext
     return url_requests_.get();
   }
 
+  void InsertURLRequest(const URLRequest* request);
+
+  void RemoveURLRequest(const URLRequest* request);
+
   // CHECKs that no URLRequests using this context remain. Subclasses should
   // additionally call AssertNoURLRequests() within their own destructor,
   // prior to implicit destruction of subclass-owned state.
@@ -325,6 +329,10 @@ class NET_EXPORT URLRequestContext
   // to be unique.
   const char* name_;
 
+  // The largest number of outstanding URLRequests that have been created by
+  // |this| and are not yet destroyed. This doesn't need to be in CopyFrom.
+  size_t largest_outstanding_requests_count_seen_;
+
   DISALLOW_COPY_AND_ASSIGN(URLRequestContext);
 };