Add shutdown trace functions

chrome/browser/browser_main_posix.cc

Index: chrome/browser/browser_main_posix.cc
diff --git a/chrome/browser/browser_main_posix.cc b/chrome/browser/browser_main_posix.cc
index 9729f64522e50b5ea8e0c216e5a569504719d140..7b3682a1bf540dedba3ff5ffe7ac41ddee2c8595 100644
--- a/chrome/browser/browser_main_posix.cc
+++ b/chrome/browser/browser_main_posix.cc
@@ -89,6 +89,23 @@ ShutdownDetector::ShutdownDetector(int shutdown_fd)
   CHECK_NE(shutdown_fd_, -1);
 }
 
+
+// These functions are used to help us diagnose crash dumps that happen
+// during the shutdown process.
+#define NOINLINE __attribute__((noinline))
+
+NOINLINE void ShutdownFDReadError() {
+  sleep(UINT_MAX);

[willchan no longer on Chromium, 2011/05/04 21:06:49]

I think you need <limits.h> for this constant and <unistd.h> for sleep (or you
could use PlatformThread::Sleep(), which might make this easier to port to
Windows if we ever do that).

Note that the noinline attribute is probably gcc only and this will probably
cause the clang bot to break. You should probably add this to
compiler_specific.h.

Also, I'm not completely sure this works, please note
http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html says: 
=====
noinline
This function attribute prevents a function from being considered for inlining.
If the function does not have side-effects, there are optimizations other than
inlining that causes function calls to be optimized away, although the function
call is live. To keep such calls from being optimized away, put
          asm ("");
     
(see Extended Asm) in the called function, to serve as a special side-effect.
=====

I think sleep() counts as a side effect, so it probably works as is, but I
thought I'd point that out.

[DaveMoore, 2011/05/09 17:41:42]

Done. I kept the sleep() call, added the asm("") and included the necessary
files.

+}
+
+NOINLINE void ShutdownFDClosedError() {
+  sleep(UINT_MAX);
+}
+
+NOINLINE void CloseAllBrowsersAndExitPosted() {
+  sleep(UINT_MAX);
+}
+
 void ShutdownDetector::ThreadMain() {
   base::PlatformThread::SetName("CrShutdownDetector");
 
@@ -102,9 +119,11 @@ void ShutdownDetector::ThreadMain() {
              sizeof(signal) - bytes_read));
     if (ret < 0) {
       NOTREACHED() << "Unexpected error: " << strerror(errno);
+      ShutdownFDReadError();
       break;
     } else if (ret == 0) {
       NOTREACHED() << "Unexpected closure of shutdown pipe.";
+      ShutdownFDClosedError();
       break;
     }
     bytes_read += ret;
@@ -134,6 +153,7 @@ void ShutdownDetector::ThreadMain() {
     RAW_LOG(WARNING, "Still here, exiting really ungracefully.");
     _exit(signal | (1 << 7));
   }
+  CloseAllBrowsersAndExitPosted();
 }
 
 // Sets the file descriptor soft limit to |max_descriptors| or the OS hard