Copy the thread name to the stack for debugging purposes.

base/threading/thread.cc

Index: base/threading/thread.cc
diff --git a/base/threading/thread.cc b/base/threading/thread.cc
index aca4ddbaa02a11c37ef02b39b5e4c3da829f404e..01be67fb1c24b07b7d5c058032bf57a7e698ffa5 100644
--- a/base/threading/thread.cc
+++ b/base/threading/thread.cc
@@ -172,6 +172,18 @@ bool Thread::GetThreadWasQuitProperly() {
 
 void Thread::ThreadMain() {
   {
+#if defined(OS_MACOSX)
+    // Store the thread name on the stack to debug <http://crbug.com/274705>.
+    // End with a byte sequence of <EOT><BEL><NUL> to make it easier to grep in
+    // the minidump stack dump.

[Mark Mentovai, 2013/09/12 18:38:37]

If you’re trying to make it easier to find in a minidump, you probably also want
to zero out unused bytes so that they don’t look like garbage.

[Robert Sesek, 2013/09/12 18:47:53]

If strlen(s2) < n, then it fills the remainder with \0. But I {0} it for you.

+    const size_t kThreadNameSize = 50;
+    char thread_name[kThreadNameSize];
+    strncpy(thread_name, name_.c_str(), kThreadNameSize);
+    thread_name[kThreadNameSize - 1] = '\0';
+    thread_name[kThreadNameSize - 2] = '\7';
+    thread_name[kThreadNameSize - 3] = '\3';

[Mark Mentovai, 2013/09/12 18:38:37]

How are you assuring that storage for variable, unused after this point, won’t
be recycled for other purposes by an optimizing compiler? For that matter, the
compiler may have sufficient intelligence to reason that this code is all
side-effect-free and completely optimize it out entirely.

[Robert Sesek, 2013/09/12 18:47:53]

Good point. Using base::debug::Alias() now at the top and bottom of this scope.

+#endif
+
     // The message loop for this thread.
     // Allocated on the heap to centralize any leak reports at this line.
     scoped_ptr<MessageLoop> message_loop(