Mojo: Change how we handle invalid pointer arguments (at the system layer).

mojo/system/core_test_base.cc

Index: mojo/system/core_test_base.cc
diff --git a/mojo/system/core_test_base.cc b/mojo/system/core_test_base.cc
index c91437c42c655162be93c987331f15ec8a9f0c84..c02b1188c1204f0a3f9af4c9075db6b294bad770 100644
--- a/mojo/system/core_test_base.cc
+++ b/mojo/system/core_test_base.cc
@@ -68,8 +68,8 @@ class MockDispatcher : public Dispatcher {
   virtual MojoResult ReadMessageImplNoLock(
       void* bytes,
       uint32_t* num_bytes,
-      DispatcherVector* /*dispatchers*/,
-      uint32_t* /*num_dispatchers*/,
+      DispatcherVector* dispatchers,
+      uint32_t* num_dispatchers,
       MojoReadMessageFlags /*flags*/) OVERRIDE {
     info_->IncrementReadMessageCallCount();
     lock().AssertAcquired();
@@ -77,6 +77,14 @@ class MockDispatcher : public Dispatcher {
     if (num_bytes && !VerifyUserPointerWithSize<1>(bytes, *num_bytes))
       return MOJO_RESULT_INVALID_ARGUMENT;
 
+    if (num_dispatchers) {
+      *num_dispatchers = 1;
+      if (dispatchers) {
+        // Okay to leave an invalid dispatcher.
+        dispatchers->resize(1);
+      }
+    }
+
     return MOJO_RESULT_OK;
   }