Simulated Crash reporting for ErrAborted requests

net/url_request/url_request.cc

Index: net/url_request/url_request.cc
diff --git a/net/url_request/url_request.cc b/net/url_request/url_request.cc
index cff804c8e6e2a20b138b3f57165938455dc8c417..110497ec999d7486e48af01469e8a68af19e5641 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -8,11 +8,14 @@
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "base/debug/alias.h"
+#include "base/debug/dump_without_crashing.h"
 #include "base/debug/stack_trace.h"
 #include "base/lazy_instance.h"
 #include "base/memory/singleton.h"
 #include "base/message_loop/message_loop.h"
 #include "base/profiler/scoped_tracker.h"
+#include "base/rand_util.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
@@ -682,6 +685,16 @@ void URLRequest::CancelWithSSLError(int error, const SSLInfo& ssl_info) {
 
 void URLRequest::DoCancel(int error, const SSLInfo& ssl_info) {
   DCHECK(error < 0);
+  // ~500,000 ERR_ABORTED < 100ms in Canary channel a day. Sample .01% to get

[eroman, 2015/11/20 02:21:43]

Thanks for doing some estimates!

I would also suggest adding a per-user maximum as a safety net for users that
are hitting thousands and thousands of these.

+  // ~50 reports a day.
+  double millis = (base::TimeTicks::Now() - creation_time_).InMillisecondsF();

[cbentzel, 2015/11/19 01:14:47]

Why are you converting to a double instead of just using integratl units?

[Charlie Harrison, 2015/11/19 02:14:25]

No real reason. I can change it back if you want.

[cbentzel, 2015/11/20 01:05:33]

Yes - doing conversion doesn't seem to be doing anything since just checking
100.0. Not sure if it will be easier to decipher integral values in stack traces
as well.

+  if (error == ERR_ABORTED && millis < 100.0 && load_flags_ & LOAD_MAIN_FRAME &&
+      base::RandDouble() < .0001) {
+    GURL url_copy = url();
+    base::debug::Alias(&url_copy);

[eroman, 2015/11/20 02:21:43]

This may not save the information you want (because the string contents to alias
may not be directly in the url_copy object).

A more reliable way to save strings into minidumps is [1]

    char url_copy[256] = {0};
    base::debug::Alias(&url_copy);
    strncpy(url_copy, url().c_str(), sizeof(url_copy));


[1] Hard to say current version will be included or not. If the URL is small,
thanks to small-string optimization it will be there. If it is larger, the
heap-allocated buffer may or may not be reachable in the minidump (dump
generation has some heuristics to include memory some pages for memory pointed
to by the stack). To be safe just copy it onto stack directly.

+    base::debug::Alias(&millis);
+    base::debug::DumpWithoutCrashing();

[eroman, 2015/11/20 02:21:43]

Please also add a TODO somewhere to delete this code once experiment is done.

+  }
   // If cancelled while calling a delegate, clear delegate info.
   if (calling_delegate_) {
     LogUnblocked();