Second reland: Introduce mojo interface for collecting StackSamplingProfiler data

components/metrics/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 declare_args() {
   # Overrides os name in uma metrics log to "Blimp".
   metrics_use_blimp = false
 }
 
 # These are only used by the blimp team, which has entirely migrated to gn,
@@ skipping 222 matching lines @@
 
     public_deps = [
       ":profiler",
     ]
     deps = [
       "//base",
     ]
   }
 }
 
+static_library("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
   sources = [
     "test_enabled_state_provider.cc",
     "test_enabled_state_provider.h",
     "test_metrics_provider.cc",
     "test_metrics_provider.h",
     "test_metrics_service_client.cc",
     "test_metrics_service_client.h",
@@ skipping 46 matching lines @@
     "ui/screen_info_metrics_provider_unittest.cc",
   ]
 
   deps = [
     ":metrics",
     ":net",
     ":profiler",
     ":test_support",
     ":ui",
     "//base/test:test_support",
+    "//components/metrics/public/cpp:call_stack_unit_tests",
     "//components/prefs:test_support",
     "//components/variations",
     "//net:test_support",
     "//testing/gtest",
     "//third_party/zlib:compression_utils",
     "//ui/gfx/geometry",
   ]
 
   if (is_linux) {
     sources += [ "serialization/serialization_utils_unittest.cc" ]
     deps += [ ":serialization" ]
   }
 
   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" ]
+  }

[Ilya Sherman, 2016/08/19 23:09:31]

Hmm, why did you move this to here?  If it can be in the more focused BUILD.gn
file, that would be better.

[Mike Wittman, 2016/08/19 23:27:54]

The previous approach still transitively added the call_stack_unit_tests' own
deps to the unit_tests source set on iOS. This is a little cleaner since it
doesn't do that.

Either approach here is likely to be reworked substantially as this interface is
integrated into the metrics and chrome code, so it's probably not worth focusing
too finely on the details at the moment.

 }