wait for DM status thread to exit on iOS

CQ_INCLUDE_TRYBOTS=skia.primary:Test-iOS-Clang-iPadPro-GPU-GT7800-arm64-Debug,Test-iOS-Clang-iPhone6-GPU-GX6450-arm64-Debug,Test-iOS-Clang-iPhone7-GPU-GT7600-arm64-Debug

Change-Id: I0e7491a6aaad08e969ceaabae49cbda718ea4be8
Reviewed-on: https://skia-review.googlesource.com/18065
Reviewed-by: Stephan Altmueller <stephana@google.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 2f7dd21e34..049621038b 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -1294,9 +1294,11 @@ static void run_test(skiatest::Test test, const GrContextOptions& grCtxOptions)
 
 DEFINE_int32(status_sec, 15, "Print status this often (and if we crash).");
 
+static std::atomic<bool> gStopStatusThread{false};
+
 SkThread* start_status_thread() {
     auto thread = new SkThread([] (void*) {
-        for (;;) {
+        while (!gStopStatusThread.load()) {
             print_status();
         #if defined(SK_BUILD_FOR_WIN)
             Sleep(FLAGS_status_sec * 1000);
@@ -1430,6 +1432,13 @@ int main(int argc, char** argv) {
     SkPDFImageDumpStats();
 #endif  // SK_PDF_IMAGE_STATS
 
+    // An experiment to work around problems with libmobiledevice driving DM.
+    // Make sure the status thread has stopped completely before we exit.
+#if defined(SK_BUILD_FOR_IOS)
+    gStopStatusThread.store(true);
+    statusThread->join();
+#endif
+
     print_status();
     SkGraphics::PurgeAllCaches();
     info("Finished!\n");