Add UMA to track the number of live URLRequests.

net/url_request/url_request_context.cc

Index: net/url_request/url_request_context.cc
diff --git a/net/url_request/url_request_context.cc b/net/url_request/url_request_context.cc
index 0ec1db63efcd31e5648fe898b009bf4dda0b5730..c7e44779ca906c5423145e2ffb66d82166427df3 100644
--- a/net/url_request/url_request_context.cc
+++ b/net/url_request/url_request_context.cc
@@ -9,6 +9,7 @@
 #include "base/compiler_specific.h"
 #include "base/debug/alias.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -48,10 +49,10 @@ URLRequestContext::URLRequestContext()
       sdch_manager_(nullptr),
       network_quality_estimator_(nullptr),
       reporting_service_(nullptr),
-      url_requests_(new std::set<const URLRequest*>),
       enable_brotli_(false),
       check_cleartext_permitted_(false),
-      name_(nullptr) {
+      name_(nullptr),
+      largest_outstanding_requests_count_seen_(0) {
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       this, "URLRequestContext", base::ThreadTaskRunnerHandle::Get());
 }
@@ -122,13 +123,27 @@ void URLRequestContext::set_cookie_store(CookieStore* cookie_store) {
   cookie_store_ = cookie_store;
 }
 
+void URLRequestContext::InsertURLRequest(const URLRequest* request) const {
+  url_requests_.insert(request);
+  if (url_requests_.size() > largest_outstanding_requests_count_seen_) {
+    largest_outstanding_requests_count_seen_ = url_requests_.size();
+    UMA_HISTOGRAM_COUNTS_1M("Net.URLRequestContext.OutstandingRequests",
+                            largest_outstanding_requests_count_seen_);
+  }
+}
+
+void URLRequestContext::RemoveURLRequest(const URLRequest* request) const {
+  DCHECK_EQ(1u, url_requests_.count(request));
+  url_requests_.erase(request);
+}
+
 void URLRequestContext::AssertNoURLRequests() const {
-  int num_requests = url_requests_->size();
+  int num_requests = url_requests_.size();
   if (num_requests != 0) {
     // We're leaking URLRequests :( Dump the URL of the first one and record how
     // many we leaked so we have an idea of how bad it is.
     char url_buf[128];
-    const URLRequest* request = *url_requests_->begin();
+    const URLRequest* request = *url_requests_.begin();
     base::strlcpy(url_buf, request->url().spec().c_str(), arraysize(url_buf));
     int load_flags = request->load_flags();
     base::debug::Alias(url_buf);
@@ -154,7 +169,7 @@ bool URLRequestContext::OnMemoryDump(
       pmd->CreateAllocatorDump(dump_name);
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameObjectCount,
                   base::trace_event::MemoryAllocatorDump::kUnitsObjects,
-                  url_requests_->size());
+                  url_requests_.size());
   HttpTransactionFactory* transaction_factory = http_transaction_factory();
   if (transaction_factory) {
     HttpNetworkSession* network_session = transaction_factory->GetSession();