Mojo EDK: Introduce MojoQueryHandleSignalsState API

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifdef __cplusplus
 #error "This file should be compiled as C, not C++."
 #endif
 
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 36 matching lines @@
   char buffer[200] = {0};
   uint32_t num_bytes;
 
   ticks = MojoGetTimeTicksNow();
   EXPECT_NE(ticks, 0);
 
   handle0 = MOJO_HANDLE_INVALID;
   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));
 
   handle1 = MOJO_HANDLE_INVALID;
   EXPECT_EQ(MOJO_RESULT_OK, MojoCreateMessagePipe(NULL, &handle0, &handle1));
 
   signals = MOJO_HANDLE_SIGNAL_READABLE;
   uint32_t result_index = 123;
   struct MojoHandleSignalsState states[1];
   EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED,
@@ skipping 27 matching lines @@
   EXPECT_EQ((uint32_t)sizeof(kHello), num_bytes);
   EXPECT_EQ(0, memcmp(buffer, kHello, sizeof(kHello)));
 
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(handle0));
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(handle1));
 
   // TODO(vtl): data pipe
 
   return NULL;
 }