[Clank SSM]: Define base_profiler_test_support_library as a loadable module.

Android doesn't support shared_library (see native_library_unittest.cc).
base_profiler_test_support_library is defined as a loadable_module for
upcoming support for android in stack_sampling_profiler_test
https://chromium-review.googlesource.com/c/chromium/src/+/2055743/20

Bug: 989102
Change-Id: Iac0f2764f5177820436db93cc4966782a879308d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2075158Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744851}

base/BUILD.gn

@@ -2380,7 +2380,8 @@ if (is_win) {
 if (is_win || is_mac) {
   if (current_cpu == "x64" || (current_cpu == "arm64" && is_win)) {
     # Must be a shared library so that it can be unloaded during testing.
-    shared_library("base_profiler_test_support_library") {
+    loadable_module("base_profiler_test_support_library") {
+      testonly = true
       sources = [ "profiler/test_support_library.cc" ]
     }
   }
@@ -3014,7 +3015,7 @@ test("base_unittests") {
       "Foundation.framework",
     ]
     if (current_cpu == "x64") {
-      data_deps += [ ":base_profiler_test_support_library" ]
+      deps += [ ":base_profiler_test_support_library" ]
     }
   }
 
@@ -3101,7 +3102,7 @@ test("base_unittests") {
     deps += [ "//base:scoped_handle_test_dll" ]
     if (current_cpu == "x64" || current_cpu == "arm64") {
       sources += [ "profiler/win32_stack_frame_unwinder_unittest.cc" ]
-      data_deps += [ ":base_profiler_test_support_library" ]
+      deps += [ ":base_profiler_test_support_library" ]
     }
     sources += [ "files/os_validation_win_unittest.cc" ]
   }

base/profiler/stack_sampling_profiler_unittest.cc

@@ -234,9 +234,9 @@ NativeLibrary LoadOtherLibrary() {
   // macros in a function returning non-null.
   const auto load = [](NativeLibrary* library) {
     FilePath other_library_path;
-    ASSERT_TRUE(PathService::Get(DIR_EXE, &other_library_path));
+    ASSERT_TRUE(PathService::Get(DIR_MODULE, &other_library_path));
     other_library_path = other_library_path.AppendASCII(
-        GetNativeLibraryName("base_profiler_test_support_library"));
+        GetLoadableModuleName("base_profiler_test_support_library"));
     NativeLibraryLoadError load_error;
     *library = LoadNativeLibrary(other_library_path, &load_error);
     ASSERT_TRUE(*library) << "error loading " << other_library_path.value()

base/profiler/test_support_library.cc

@@ -5,9 +5,11 @@
 // Note: there is intentionally no header file associated with this library so
 // we don't risk implicitly demand loading it by accessing a symbol.
 
-#if defined(WIN32)
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
 #define BASE_PROFILER_TEST_SUPPORT_LIBRARY_EXPORT __declspec(dllexport)
-#else  // defined(WIN32)
+#else  // defined(OS_WIN)
 #define BASE_PROFILER_TEST_SUPPORT_LIBRARY_EXPORT __attribute__((visibility("default")))
 #endif