Remove net URLRequest trace events.

chrome/browser/net/chrome_network_delegate.cc

Index: chrome/browser/net/chrome_network_delegate.cc
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index f50add261d5ae8a9a1e5745869072a122089a396..a89ec11526cb9e1eb847945843d7d8892985e6b2 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -326,7 +326,6 @@ int ChromeNetworkDelegate::OnBeforeSendHeaders(
   if (force_safety_mode)
     safe_search_util::ForceYouTubeSafetyMode(request, headers);
 
-  TRACE_EVENT_ASYNC_STEP_PAST0("net", "URLRequest", request, "SendRequest");
   return extensions_delegate_->OnBeforeSendHeaders(request, callback, headers);
 }
 
@@ -359,7 +358,6 @@ void ChromeNetworkDelegate::OnBeforeRedirect(net::URLRequest* request,
 
 
 void ChromeNetworkDelegate::OnResponseStarted(net::URLRequest* request) {
-  TRACE_EVENT_ASYNC_STEP_PAST0("net", "URLRequest", request, "ResponseStarted");
   extensions_delegate_->OnResponseStarted(request);
 }
 
@@ -370,8 +368,6 @@ void ChromeNetworkDelegate::OnRawBytesRead(const net::URLRequest& request,
       FROM_HERE_WITH_EXPLICIT_FUNCTION(
           "423948 ChromeNetworkDelegate::OnRawBytesRead"));
 
-  TRACE_EVENT_ASYNC_STEP_PAST1("net", "URLRequest", &request, "DidRead",
-                               "bytes_read", bytes_read);
 #if defined(ENABLE_TASK_MANAGER)
   // This is not completely accurate, but as a first approximation ignore
   // requests that are served from the cache. See bug 330931 for more info.
@@ -399,7 +395,6 @@ void ChromeNetworkDelegate::OnCompleted(net::URLRequest* request,
                                         bool started) {
   RecordNetworkErrorHistograms(request);
 
-  TRACE_EVENT_ASYNC_END0("net", "URLRequest", request);
   if (request->status().status() == net::URLRequestStatus::SUCCESS) {
 #if defined(OS_ANDROID)
     // For better accuracy, we use the actual bytes read instead of the length