Handle EAGAIN error for the mincore syscall used

base/trace_event/process_memory_dump_unittest.cc

Index: base/trace_event/process_memory_dump_unittest.cc
diff --git a/base/trace_event/process_memory_dump_unittest.cc b/base/trace_event/process_memory_dump_unittest.cc
index 132bb475bd3a10f642ba544b3afe6df23228c928..afdefaf6dfd606cf6c4c94809c0d3857635b4a3e 100644
--- a/base/trace_event/process_memory_dump_unittest.cc
+++ b/base/trace_event/process_memory_dump_unittest.cc
@@ -164,17 +164,21 @@ TEST(ProcessMemoryDumpTest, CountResidentBytes) {
   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)