Multiprocess test client: Android child process launcher rework.

mojo/edk/test/run_all_unittests.cc

Index: mojo/edk/test/run_all_unittests.cc
diff --git a/mojo/edk/test/run_all_unittests.cc b/mojo/edk/test/run_all_unittests.cc
index cd6b241d605b05c6b8982303a3fa8e8a51ddaff3..1a8193875ece55539157f9d3963797d657023f6a 100644
--- a/mojo/edk/test/run_all_unittests.cc
+++ b/mojo/edk/test/run_all_unittests.cc
@@ -17,6 +17,16 @@
 #include "mojo/public/tests/test_support_private.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_ANDROID)
+#include "base/test/android/android_main_function_thunk.h"
+
+int main(int argc, char** argv);
+namespace {
+// Needed for multiprocess tests to find the main function.
+base::android::AndroidMainFunctionThunk main_thunk(&main);

[Ken Rockot(use gerrit already), 2016/12/12 22:23:08]

Unfortunately I'm reminded that use of non-constexpr static initializers is
explicitly forbidden by the style guide, and there's no way for this constructor
to be constexpr. Maybe someone has a more clever idea for injecting an entry
point without forcing an extra link-time requirement on all dependents. e.g. it
would be lame if we declared something like base::android::AndroidTestClientMain
and required all targets to define it.

[Jay Civelli, 2016/12/13 18:23:26]

Per our discussion, I created a main_stub and made the few targets that depend
on base:test_support but don't have a main depend on it.

+}
+#endif
+
 int main(int argc, char** argv) {
 #if !defined(OS_ANDROID)
   // Silence death test thread warnings on Linux. We can afford to run our death
@@ -26,10 +36,6 @@ int main(int argc, char** argv) {
   testing::GTEST_FLAG(death_test_style) = "threadsafe";
 #endif
 #if defined(OS_ANDROID)
-  // Enable the alternate test child implementation. This is needed because Mojo
-  // tests need to spawn test children after initialising the Mojo system.
-  base::InitAndroidMultiProcessTestHelper(main);
-
   // On android, the test framework has a signal handler that will print a
   // [ CRASH ] line when the application crashes. This breaks death test has the
   // test runner will consider the death of the child process a test failure.