Mojo: Optimize VerifyUserPointer().

mojo/public/tests/system_core_perftest.cc

Index: mojo/public/tests/system_core_perftest.cc
diff --git a/mojo/public/tests/system_core_perftest.cc b/mojo/public/tests/system_core_perftest.cc
index 2e9fef22a078b5c58e3536f8d3dfa7d6b8225dc1..8ee7ceb2cc7be1e8015c180a0bae534f84fe9e5b 100644
--- a/mojo/public/tests/system_core_perftest.cc
+++ b/mojo/public/tests/system_core_perftest.cc
@@ -45,6 +45,15 @@ class SystemPerftest : public test::TestBase {
     DCHECK_EQ(result, MOJO_RESULT_OK);
   }
 
+  void MessagePipe_EmptyRead() {
+    MojoResult result;
+    result = ReadMessage(h_0_,
+                         NULL, NULL,
+                         NULL, NULL,
+                         MOJO_READ_MESSAGE_FLAG_MAY_DISCARD);
+    DCHECK_EQ(result, MOJO_RESULT_NOT_FOUND);
+  }
+
  protected:
   Handle h_0_;
   Handle h_1_;
@@ -95,5 +104,15 @@ TEST_F(SystemPerftest, MessagePipe_WriteAndRead) {
   CHECK_EQ(Close(h_1_), MOJO_RESULT_OK);
 }
 
+TEST_F(SystemPerftest, MessagePipe_EmptyRead) {
+  CHECK_EQ(CreateMessagePipe(&h_0_, &h_1_), MOJO_RESULT_OK);
+  test::IterateAndReportPerf(
+      "MessagePipe_EmptyRead",
+      base::Bind(&SystemPerftest::MessagePipe_EmptyRead,
+                 base::Unretained(this)));
+  CHECK_EQ(Close(h_0_), MOJO_RESULT_OK);
+  CHECK_EQ(Close(h_1_), MOJO_RESULT_OK);
+}
+
 }  // namespace
 }  // namespace mojo