Doc: SIGUSR1 needed when paused for debugger.

content/common/child_process.cc

Index: content/common/child_process.cc
diff --git a/content/common/child_process.cc b/content/common/child_process.cc
index 6e5d9a45d5f6ae4e6dd58e86d34793c93b862079..75c80ecd24a64f646e965aa65352b764196b2f25 100644
--- a/content/common/child_process.cc
+++ b/content/common/child_process.cc
@@ -133,7 +133,8 @@ void ChildProcess::WaitForDebugger(const std::string& label) {
   LOG(ERROR) << label
              << " ("
              << getpid()
-             << ") paused waiting for debugger to attach @ pid";
+             << ") paused waiting for debugger to attach. "
+             << "Send SIGUSR1 to unpause.";
   // Install a signal handler so that pause can be woken.
   struct sigaction sa;
   memset(&sa, 0, sizeof(sa));