Disable two tests in mojo_system_unittests that are suspected to be timing out

mojo/edk/embedder/embedder_unittest.cc

 // 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.
 
 #include "mojo/edk/embedder/embedder.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
 
@@ skipping 206 matching lines @@
   // Close the remote end, simulating child death before the child connects to
   // the reserved port.
   ignore_result(pair.PassClientHandle());
 
   EXPECT_EQ(MOJO_RESULT_OK, MojoWait(parent_mp.get().value(),
                                      MOJO_HANDLE_SIGNAL_PEER_CLOSED,
                                      MOJO_DEADLINE_INDEFINITE,
                                      nullptr));
 }
 
-TEST_F(EmbedderTest, PipeSetup_LaunchFailure) {
+#if defined(OS_ANDROID)
+// This test is suspected to be flaky on android https://crbug.com/663998.
+#define MAYBE_PipeSetup_LaunchFailure \
+    DISABLED_PipeSetup_LaunchFailure
+#else
+#define MAYBE_PipeSetup_LaunchFailure \
+    PipeSetup_LaunchFailure
+#endif
+TEST_F(EmbedderTest, MAYBE_PipeSetup_LaunchFailure) {
   PlatformChannelPair pair;
 
   std::string child_token = GenerateRandomToken();
   std::string pipe_token = GenerateRandomToken();
 
   ScopedMessagePipeHandle parent_mp =
       CreateParentMessagePipe(pipe_token, child_token);
 
   ChildProcessLaunchFailed(child_token);
   EXPECT_EQ(MOJO_RESULT_OK, MojoWait(parent_mp.get().value(),
@@ skipping 415 matching lines @@
                                   client_mp) {
   ASSERT_EQ(MOJO_RESULT_OK, MojoWait(client_mp, MOJO_HANDLE_SIGNAL_PEER_CLOSED,
                                      MOJO_DEADLINE_INDEFINITE, nullptr));
 }
 
 #endif  // !defined(OS_IOS)
 
 }  // namespace
 }  // namespace edk
 }  // namespace mojo