Handle correctly "ShouldWait" result of mojo::Wait() in WebDataConsumerHandleImpl.

content/child/web_data_consumer_handle_impl.cc

Index: content/child/web_data_consumer_handle_impl.cc
diff --git a/content/child/web_data_consumer_handle_impl.cc b/content/child/web_data_consumer_handle_impl.cc
index 50433a3a3b957ce672f4e91e47ce96e48288b51d..fdec9c9881ec3596b464f8a9c800e1608c73fd51 100644
--- a/content/child/web_data_consumer_handle_impl.cc
+++ b/content/child/web_data_consumer_handle_impl.cc
@@ -61,8 +61,19 @@ Result WebDataConsumerHandleImpl::ReaderImpl::read(void* data,
     // FAILED_PRECONDITION when |size| is 0 and the producer handle was closed.
     // But in this case, WebDataConsumerHandle::Reader::read() must return Ok.
     // So we use mojo::Wait() with 0 deadline to check whether readable or not.
-    return HandleReadResult(mojo::Wait(
-        context_->handle().get(), MOJO_HANDLE_SIGNAL_READABLE, 0, nullptr));
+    MojoResult wait_result = mojo::Wait(
+        context_->handle().get(), MOJO_HANDLE_SIGNAL_READABLE, 0, nullptr);
+    switch (wait_result) {
+      case MOJO_RESULT_OK:
+        return Ok;
+      case MOJO_RESULT_FAILED_PRECONDITION:
+        return Done;
+      case MOJO_RESULT_DEADLINE_EXCEEDED:
+        return ShouldWait;
+      default:
+        NOTREACHED();
+        return UnexpectedError;
+    }
   }
 
   uint32_t size_to_pass = size;