Revert of Multiprocess test client: Android child process launcher rework.

base/process/process_util_unittest.cc

Index: base/process/process_util_unittest.cc
diff --git a/base/process/process_util_unittest.cc b/base/process/process_util_unittest.cc
index 7031706e0b7796721e098ca6b72aa2b8b126b7f6..87fdd0123097e51739a2bc1830e34f584302fdc8 100644
--- a/base/process/process_util_unittest.cc
+++ b/base/process/process_util_unittest.cc
@@ -257,7 +257,7 @@
 }
 #endif  // defined(OS_WIN)
 
-#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
+#if !defined(OS_MACOSX)
 // This test is disabled on Mac, since it's flaky due to ReportCrash
 // taking a variable amount of time to parse and load the debug and
 // symbol data for this unit test's executable before firing the
@@ -266,14 +266,23 @@
 // TODO(gspencer): turn this test process into a very small program
 // with no symbols (instead of using the multiprocess testing
 // framework) to reduce the ReportCrash overhead.
-//
-// It is disabled on Android as MultiprocessTests are started as services that
-// the framework restarts on crashes.
 const char kSignalFileCrash[] = "CrashingChildProcess.die";
 
 MULTIPROCESS_TEST_MAIN(CrashingChildProcess) {
   WaitToDie(ProcessUtilTest::GetSignalFilePath(kSignalFileCrash).c_str());
-#if defined(OS_POSIX)
+#if defined(OS_ANDROID)
+  // Android L+ expose signal and sigaction symbols that override the system
+  // ones. There is a bug in these functions where a request to set the handler
+  // to SIG_DFL is ignored. In that case, an infinite loop is entered as the
+  // signal is repeatedly sent to the crash dump signal handler.
+  // To work around this, directly call the system's sigaction.
+  struct kernel_sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sys_sigemptyset(&sa.sa_mask);
+  sa.sa_handler_ = SIG_DFL;
+  sa.sa_flags = SA_RESTART;
+  sys_rt_sigaction(SIGSEGV, &sa, NULL, sizeof(kernel_sigset_t));
+#elif defined(OS_POSIX)
   // Have to disable to signal handler for segv so we can get a crash
   // instead of an abnormal termination through the crash dump handler.
   ::signal(SIGSEGV, SIG_DFL);
@@ -322,7 +331,7 @@
   base::debug::EnableInProcessStackDumping();
   remove(signal_file.c_str());
 }
-#endif  // !defined(OS_MACOSX) && !defined(OS_ANDROID)
+#endif  // !defined(OS_MACOSX)
 
 MULTIPROCESS_TEST_MAIN(KilledChildProcess) {
   WaitToDie(ProcessUtilTest::GetSignalFilePath(kSignalFileKill).c_str());