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

mojo/edk/system/data_pipe_impl.h

Index: mojo/edk/system/data_pipe_impl.h
diff --git a/mojo/edk/system/data_pipe_impl.h b/mojo/edk/system/data_pipe_impl.h
index eff67353894313f4d5525e92593ab14eede8dbfa..6dfddc70cfe9cbf2560e42d430f4a3b4d43faca8 100644
--- a/mojo/edk/system/data_pipe_impl.h
+++ b/mojo/edk/system/data_pipe_impl.h
@@ -64,8 +64,7 @@ class DataPipeImpl {
                                        uint32_t min_num_bytes_to_write) = 0;
   virtual MojoResult ProducerBeginWriteData(
       UserPointer<void*> buffer,
-      UserPointer<uint32_t> buffer_num_bytes,
-      uint32_t min_num_bytes_to_write) = 0;
+      UserPointer<uint32_t> buffer_num_bytes) = 0;
   virtual MojoResult ProducerEndWriteData(uint32_t num_bytes_written) = 0;
   // Note: A producer should not be writable during a two-phase write.
   virtual HandleSignalsState ProducerGetHandleSignalsState() const = 0;
@@ -92,8 +91,7 @@ class DataPipeImpl {
   virtual MojoResult ConsumerQueryData(UserPointer<uint32_t> num_bytes) = 0;
   virtual MojoResult ConsumerBeginReadData(
       UserPointer<const void*> buffer,
-      UserPointer<uint32_t> buffer_num_bytes,
-      uint32_t min_num_bytes_to_read) = 0;
+      UserPointer<uint32_t> buffer_num_bytes) = 0;
   virtual MojoResult ConsumerEndReadData(uint32_t num_bytes_read) = 0;
   // Note: A consumer should not be writable during a two-phase read.
   virtual HandleSignalsState ConsumerGetHandleSignalsState() const = 0;