Handle EAGAIN error for the mincore syscall used

base/trace_event/process_memory_dump_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 "base/trace_event/process_memory_dump.h"
 
 #include "base/memory/aligned_memory.h"
 #include "base/process/process_metrics.h"
 #include "base/trace_event/memory_allocator_dump_guid.h"
 #include "base/trace_event/trace_event_argument.h"
@@ skipping 146 matching lines @@
 
 #if defined(COUNT_RESIDENT_BYTES_SUPPORTED)
 TEST(ProcessMemoryDumpTest, CountResidentBytes) {
   const size_t page_size = base::GetPageSize();
 
   // Allocate few page of dirty memory and check if it is resident.
   const size_t size1 = 5 * page_size;
   scoped_ptr<char, base::AlignedFreeDeleter> memory1(
       static_cast<char*>(base::AlignedAlloc(size1, page_size)));
   memset(memory1.get(), 0, size1);
-  size_t res1 = ProcessMemoryDump::CountResidentBytes(memory1.get(), size1);
-  ASSERT_EQ(res1, size1);
+  size_t res1 = 0;
+  bool ret = ProcessMemoryDump::CountResidentBytes(memory1.get(), size1, &res1);
+  ASSERT_TRUE(ret);
+  ASSERT_EQ(size1, res1);
 
   // Allocate a large memory segment (>32Mib).
   const size_t kVeryLargeMemorySize = 34 * 1024 * 1024;
   scoped_ptr<char, base::AlignedFreeDeleter> memory2(
       static_cast<char*>(base::AlignedAlloc(kVeryLargeMemorySize, page_size)));
   memset(memory2.get(), 0, kVeryLargeMemorySize);
-  size_t res2 = ProcessMemoryDump::CountResidentBytes(memory2.get(),
-                                                      kVeryLargeMemorySize);
-  ASSERT_EQ(res2, kVeryLargeMemorySize);
+  size_t res2 = 0;
+  ret = ProcessMemoryDump::CountResidentBytes(memory2.get(),
+                                              kVeryLargeMemorySize, &res2);
+  ASSERT_TRUE(ret);
+  ASSERT_EQ(kVeryLargeMemorySize, res2);
 }
 #endif  // defined(COUNT_RESIDENT_BYTES_SUPPORTED)
 
 }  // namespace trace_event
 }  // namespace base