NativeStackSampler implementation for Mac.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 11236dcd171b1a85d861094613942425e6432490..60e1929129a4f153626df2380ee652690af9e0c3 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -712,6 +712,7 @@ component("base") {
     "process/process_win.cc",
     "profiler/native_stack_sampler.cc",
     "profiler/native_stack_sampler.h",
+    "profiler/native_stack_sampler_mac.cc",
     "profiler/native_stack_sampler_posix.cc",
     "profiler/native_stack_sampler_win.cc",
     "profiler/scoped_profile.cc",
@@ -1451,6 +1452,10 @@ component("base") {
       "strings/sys_string_conversions_posix.cc",
       "threading/platform_thread_internal_posix.cc",
     ]
+
+    if (is_mac) {
+      sources -= [ "profiler/native_stack_sampler_posix.cc" ]
+    }
   } else {
     # Non-Mac/ios.
     sources -= [
@@ -1815,7 +1820,9 @@ if (is_win) {
       "//base/win:base_win_features",
     ]
   }
+}
 
+if (is_win || is_mac) {
   if (current_cpu == "x64") {
     # Must be a shared library so that it can be unloaded during testing.
     shared_library("base_profiler_test_support_library") {

[Mark Mentovai, 2017/02/17 05:21:05]

I believe you want this to be a loadable_module and not a shared_library.
Dependents don’t link against loadable modules (as opposed to shared libraries),
so that you can be in charge of loading them yourself.

[Avi (use Gerrit), 2017/02/17 17:18:12]

Done.

[Avi (use Gerrit), 2017/02/17 17:47:40]

This results in an .so file, which isn't dynamically openable by LoadLibrary.
Reverting just this part.

@@ -2266,6 +2273,9 @@ test("base_unittests") {
       "CoreFoundation.framework",
       "Foundation.framework",
     ]
+    if (current_cpu == "x64") {
+      data_deps += [ ":base_profiler_test_support_library" ]
+    }
   }
 
   if (is_linux) {
@@ -2304,7 +2314,7 @@ test("base_unittests") {
     deps += [ "//base:scoped_handle_test_dll" ]
     if (current_cpu == "x64") {
       sources += [ "profiler/win32_stack_frame_unwinder_unittest.cc" ]
-      deps += [ ":base_profiler_test_support_library" ]
+      data_deps += [ ":base_profiler_test_support_library" ]
     }
   }