android: re-enable a library_prefetcher test, expect for ASAN.

Bug: 570423
Change-Id: I8a64245abeaec3ea334345d0ae27e660c5d7d63f
Reviewed-on: https://chromium-review.googlesource.com/632623Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Benoit L <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#497353}

base/android/library_loader/library_prefetcher_unittest.cc

@@ -11,6 +11,7 @@
 #include <vector>
 #include "base/debug/proc_maps_linux.h"
 #include "base/memory/shared_memory.h"
+#include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
@@ -22,7 +23,6 @@ const uint8_t kReadPrivate = base::debug::MappedMemoryRegion::READ |
                              base::debug::MappedMemoryRegion::PRIVATE;
 const uint8_t kExecutePrivate = base::debug::MappedMemoryRegion::EXECUTE |
                                 base::debug::MappedMemoryRegion::PRIVATE;
-const size_t kPageSize = 4096;
 }  // namespace
 
 TEST(NativeLibraryPrefetcherTest, TestIsGoodToPrefetchNoRange) {
@@ -96,6 +96,12 @@ TEST(NativeLibraryPrefetcherTest,
   EXPECT_EQ(ranges[0].second, 0x7U);
 }
 
+// Fails with ASAN, crbug.com/570423.
+#if !defined(ADDRESS_SANITIZER)
+namespace {
+const size_t kPageSize = 4096;
+}  // namespace
+
 TEST(NativeLibraryPrefetcherTest, DISABLED_TestPercentageOfResidentCode) {
   size_t length = 4 * kPageSize;
   base::SharedMemory shared_mem;
@@ -150,6 +156,7 @@ TEST(NativeLibraryPrefetcherTest,
   munlock(address, length);
   munlock(address2, length);
 }
+#endif  // !defined(ADDRESS_SANITIZER)
 
 }  // namespace android
 }  // namespace base