Mojo EDK: Introduce MojoQueryHandleSignalsState API

mojo/public/c/system/tests/core_unittest_pure_c.c

Index: mojo/public/c/system/tests/core_unittest_pure_c.c
diff --git a/mojo/public/c/system/tests/core_unittest_pure_c.c b/mojo/public/c/system/tests/core_unittest_pure_c.c
index fa3caa5e681f538c4583b0b2b26e2959ec40e53d..890bcfac91e9e48c9dfbd3c23060a45de3a82442 100644
--- a/mojo/public/c/system/tests/core_unittest_pure_c.c
+++ b/mojo/public/c/system/tests/core_unittest_pure_c.c
@@ -54,6 +54,9 @@ const char* MinimalCTest(void) {
   EXPECT_NE(MOJO_RESULT_OK, MojoClose(handle0));
 
   EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
+            MojoQueryHandleSignalsState(handle0, NULL));
+
+  EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
             MojoWait(handle0, ~MOJO_HANDLE_SIGNAL_NONE,
                      MOJO_DEADLINE_INDEFINITE, NULL));