Emit VMRegions for macOS when doing process memory dumps.

components/tracing/common/process_metrics_memory_dump_provider_unittest.cc

Index: components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
diff --git a/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc b/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
index 5b1b25f1d0ea12f329b6d25f574c6e21438d8bc4..1c93b0b3b39fb09d6a2539d5e3e8adadf6450457 100644
--- a/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
+++ b/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
@@ -269,4 +269,30 @@ TEST(ProcessMetricsMemoryDumpProviderTest, TestPollFastMemoryTotal) {
 #endif
 }
 
+#if defined(OS_MACOSX)
+TEST(ProcessMetricsMemoryDumpProviderTest, TestMachOReading) {
+  using VMRegion = base::trace_event::ProcessMemoryMaps::VMRegion;
+  ProcessMetricsMemoryDumpProvider mdp(base::kNullProcessId);
+  base::trace_event::MemoryDumpArgs args;
+  base::trace_event::ProcessMemoryDump dump(nullptr, args);
+  ASSERT_TRUE(mdp.DumpProcessMemoryMaps(args, &dump));
+  ASSERT_TRUE(dump.has_process_mmaps());
+
+  bool found_components_unittests = false;
+  for (const VMRegion& region : dump.process_mmaps()->vm_regions()) {
+    EXPECT_NE(0u, region.start_address);
+    EXPECT_NE(0u, region.size_in_bytes);
+
+    uint32_t required_protection_flags =
+        VMRegion::kProtectionFlagsRead | VMRegion::kProtectionFlagsExec;
+    EXPECT_EQ(required_protection_flags,
+              region.protection_flags & required_protection_flags);
+    EXPECT_LT(region.size_in_bytes, 1ull << 32);
+    if (region.mapped_file.find("components_unittests") != std::string::npos)

[Mark Mentovai, 2017/01/03 20:07:46]

Might be less fragile if you used basename(_NSGetExecutablePath()) instead of
hard-coding.

+      found_components_unittests = true;
+  }
+  EXPECT_TRUE(found_components_unittests);
+}
+#endif  // defined(OS_MACOSX)
+
 }  // namespace tracing