DM: --tests -> --src tests

dm/DM.cpp

 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
 #include "OverwriteLine.h"
 #include "ProcStats.h"
 #include "SkBBHFactory.h"
 #include "SkCommonFlags.h"
 #include "SkForceLinking.h"
 #include "SkGraphics.h"
 #include "SkMD5.h"
 #include "SkOSFile.h"
 #include "SkTaskGroup.h"
 #include "Test.h"
 #include "Timer.h"
 
-DEFINE_bool(tests, true, "Run tests?");
 DEFINE_string(images, "resources", "Images to decode.");
-DEFINE_string(src, "gm skp image", "Source types to test.");
+DEFINE_string(src, "tests gm skp image", "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 0 1 0 0 0 1",
               "Matrix to apply when using 'matrix' in config.");
 DEFINE_bool(gpu_threading, false, "Allow GPU work to run on multiple threads?");
 
 DEFINE_string(blacklist, "",
         "Space-separated config/src/name triples to blacklist.  '_' matches anything.  E.g. \n"
@@ skipping 328 matching lines @@
     }
 }
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 // Unit tests don't fit so well into the Src/Sink model, so we give them special treatment.
 
 static SkTDArray<skiatest::Test> gCPUTests, gGPUTests;
 
 static void gather_tests() {
-    if (!FLAGS_tests) {
+    if (!FLAGS_src.contains("tests")) {
         return;
     }
     for (const skiatest::TestRegistry* r = skiatest::TestRegistry::Head(); r;
          r = r->next()) {
         // Despite its name, factory() is returning a reference to
         // link-time static const POD data.
         const skiatest::Test& test = r->factory();
         if (SkCommandLineFlags::ShouldSkip(FLAGS_match, test.name)) {
             continue;
         }
@@ skipping 94 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