Cleanup: Remove internal two-phase data pipe all-or-none support.

mojo/edk/system/remote_producer_data_pipe_impl.cc

Index: mojo/edk/system/remote_producer_data_pipe_impl.cc
diff --git a/mojo/edk/system/remote_producer_data_pipe_impl.cc b/mojo/edk/system/remote_producer_data_pipe_impl.cc
index 847949f386c0109ccf90048bf3dbb204cc278ee1..abf1e962c8af7fab4acf87b397fcf65578d9d5c9 100644
--- a/mojo/edk/system/remote_producer_data_pipe_impl.cc
+++ b/mojo/edk/system/remote_producer_data_pipe_impl.cc
@@ -133,8 +133,7 @@ MojoResult RemoteProducerDataPipeImpl::ProducerWriteData(
 
 MojoResult RemoteProducerDataPipeImpl::ProducerBeginWriteData(
     UserPointer<void*> /*buffer*/,
-    UserPointer<uint32_t> /*buffer_num_bytes*/,
-    uint32_t /*min_num_bytes_to_write*/) {
+    UserPointer<uint32_t> /*buffer_num_bytes*/) {
   NOTREACHED();
   return MOJO_RESULT_INTERNAL;
 }
@@ -250,16 +249,8 @@ MojoResult RemoteProducerDataPipeImpl::ConsumerQueryData(
 
 MojoResult RemoteProducerDataPipeImpl::ConsumerBeginReadData(
     UserPointer<const void*> buffer,
-    UserPointer<uint32_t> buffer_num_bytes,
-    uint32_t min_num_bytes_to_read) {
+    UserPointer<uint32_t> buffer_num_bytes) {
   size_t max_num_bytes_to_read = GetMaxNumBytesToRead();
-  if (min_num_bytes_to_read > max_num_bytes_to_read) {
-    // Don't return "should wait" since you can't wait for a specified amount of
-    // data.
-    return producer_open() ? MOJO_RESULT_OUT_OF_RANGE
-                           : MOJO_RESULT_FAILED_PRECONDITION;
-  }
-
   // Don't go into a two-phase read if there's no data.
   if (max_num_bytes_to_read == 0) {
     return producer_open() ? MOJO_RESULT_SHOULD_WAIT