Mojo: Fix data pipe ALL_OR_NONE write capacity check.

mojo/edk/system/data_pipe_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/bind.h"
@@ skipping 781 matching lines @@
 TEST_F(DataPipeTest, AllOrNone) {
   const MojoCreateDataPipeOptions options = {
       kSizeOfOptions,                           // |struct_size|.
       MOJO_CREATE_DATA_PIPE_OPTIONS_FLAG_NONE,  // |flags|.
       static_cast<uint32_t>(sizeof(int32_t)),   // |element_num_bytes|.
       10 * sizeof(int32_t)                      // |capacity_num_bytes|.
   };
   ASSERT_EQ(MOJO_RESULT_OK, Create(&options));
   MojoHandleSignalsState hss;
 
-  // Try writing way too much.
+  // Try writing more than the total capacity of the pipe.
   uint32_t num_bytes = 20u * sizeof(int32_t);
   int32_t buffer[100];
   Seq(0, arraysize(buffer), buffer);
   ASSERT_EQ(MOJO_RESULT_OUT_OF_RANGE, WriteData(buffer, &num_bytes, true));
 
   // Should still be empty.
   num_bytes = ~0u;
   ASSERT_EQ(MOJO_RESULT_OK, QueryData(&num_bytes));
   ASSERT_EQ(0u, num_bytes);
 
@@ skipping 14 matching lines @@
                      MOJO_DEADLINE_INDEFINITE, &hss));
   ASSERT_EQ(MOJO_HANDLE_SIGNAL_READABLE, hss.satisfied_signals);
   ASSERT_EQ(MOJO_HANDLE_SIGNAL_READABLE | MOJO_HANDLE_SIGNAL_PEER_CLOSED,
             hss.satisfiable_signals);
 
   // Half full.
   num_bytes = 0u;
   ASSERT_EQ(MOJO_RESULT_OK, QueryData(&num_bytes));
   ASSERT_EQ(5u * sizeof(int32_t), num_bytes);
 
-  /* TODO(jam): enable if we end up observing max capacity

[miu, 2016/09/14 22:40:23]

Not sure what the TODO comment was talking about here, but I resurrected the
commented-out test code. Please advise if there's anything extra you want me to
do here.

-  // Too much.
+  // Try writing more than the available capacity of the pipe, but less than the
+  // total capacity.
   num_bytes = 6u * sizeof(int32_t);
   Seq(200, arraysize(buffer), buffer);
   ASSERT_EQ(MOJO_RESULT_OUT_OF_RANGE, WriteData(buffer, &num_bytes, true));
-  */
 
   // Try reading too much.
   num_bytes = 11u * sizeof(int32_t);
   memset(buffer, 0xab, sizeof(buffer));
   ASSERT_EQ(MOJO_RESULT_OUT_OF_RANGE, ReadData(buffer, &num_bytes, true));
   int32_t expected_buffer[100];
   memset(expected_buffer, 0xab, sizeof(expected_buffer));
   ASSERT_EQ(0, memcmp(buffer, expected_buffer, sizeof(buffer)));
 
   // Try discarding too much.
@@ skipping 1129 matching lines @@
     for (size_t i = 3; i < 6; ++i)
       CloseHandle(producers[i]);
   END_CHILD()
 }
 
 #endif  // !defined(OS_IOS)
 
 }  // namespace
 }  // namespace edk
 }  // namespace mojo