Second reland: Introduce mojo interface for collecting StackSamplingProfiler data

components/metrics/BUILD.gn

Index: components/metrics/BUILD.gn
diff --git a/components/metrics/BUILD.gn b/components/metrics/BUILD.gn
index 95dfabbb9ad7dd92402ea8214fbe8b9b60e494e1..c0bebab5c7ac4961c5d0b2a2eee7862bb7abf678 100644
--- a/components/metrics/BUILD.gn
+++ b/components/metrics/BUILD.gn
@@ -240,6 +240,12 @@ if (!is_ios) {
   }
 }
 
+source_set("call_stacks") {
+  deps = [
+    "//components/metrics/public/interfaces:call_stack_mojo_bindings",
+  ]
+}
+
 # GYP version: components/metrics.gypi:metrics_test_support
 static_library("test_support") {
   testonly = true
@@ -306,6 +312,7 @@ source_set("unit_tests") {
     ":test_support",
     ":ui",
     "//base/test:test_support",
+    "//components/metrics/public/cpp:call_stack_unit_tests",
     "//components/prefs:test_support",
     "//components/variations",
     "//net:test_support",
@@ -322,4 +329,10 @@ source_set("unit_tests") {
   if (is_chromeos) {
     deps += [ "leak_detector:unit_tests" ]
   }
+
+  # iOS is not supported by the profiler and the ios-simulator bot chokes on
+  # this test.
+  if (is_ios) {
+    deps -= [ "//components/metrics/public/cpp:call_stack_unit_tests" ]
+  }
 }