DM: add keepalive for Valgrind bot.

dm/DM.cpp

 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
 #include "DMSrcSinkAndroid.h"
 #include "OverwriteLine.h"
 #include "ProcStats.h"
 #include "SkBBHFactory.h"
 #include "SkChecksum.h"
 #include "SkCommonFlags.h"
 #include "SkForceLinking.h"
 #include "SkGraphics.h"
 #include "SkInstCnt.h"
 #include "SkMD5.h"
 #include "SkOSFile.h"
 #include "SkTHash.h"
 #include "SkTaskGroup.h"
+#include "SkThreadUtils.h"
 #include "Test.h"
 #include "Timer.h"
 
 DEFINE_string(src, "tests gm skp image subset", "Source types to test.");
 DEFINE_bool(nameByHash, false,
             "If true, write to FLAGS_writePath[0]/<hash>.png instead of "
             "to FLAGS_writePath[0]/<config>/<sourceType>/<name>.png");
 DEFINE_bool2(pathOpsExtended, x, false, "Run extended pathOps tests.");
 DEFINE_string(matrix, "1 0 0 1",
               "2x2 scale+skew matrix to apply or upright when using "
@@ skipping 481 matching lines @@
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 // If we're isolating all GPU-bound work to one thread (the default), this function runs all that.
 static void run_enclave_and_gpu_tests(SkTArray<Task>* tasks) {
     run_enclave(tasks);
     for (int i = 0; i < gGPUTests.count(); i++) {
         run_test(&gGPUTests[i]);
     }
 }
 
+// Some runs (mostly, Valgrind) are so slow that the bot framework thinks we've hung.
+// This prints something every once in a while so that it knows we're still working.
+static void keep_alive(void*) {
+    for (;;) {
+        static const int kSec = 300;
+#if defined(SK_BUILD_FOR_WIN)
+        Sleep(kSec * 1000);
+#else
+        sleep(kSec);
+#endif
+        SkDebugf("\nStill alive: doing science, reticulating splines...\n");
+    }
+}
+
 int dm_main();
 int dm_main() {
     SetupCrashHandler();
     SkAutoGraphics ag;
     SkTaskGroup::Enabler enabled(FLAGS_threads);
     if (FLAGS_leaks) {
         SkInstCountPrintLeaksOnExit();
     }
 
+    SkThread keepAlive(keep_alive);  // This thread will just be killed by processes shutdown.
+    keepAlive.start();
+
     gather_gold();
 
     gather_srcs();
     gather_sinks();
     gather_tests();
 
     gPending = gSrcs.count() * gSinks.count() + gThreadedTests.count() + gGPUTests.count();
     SkDebugf("%d srcs * %d sinks + %d tests == %d tasks\n",
              gSrcs.count(), gSinks.count(), gThreadedTests.count() + gGPUTests.count(), gPending);
 
@@ skipping 41 matching lines @@
     }
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif