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..5097279f1859b31a4ac3c5c215843fbd6a616e5a 100644
--- a/components/metrics/BUILD.gn
+++ b/components/metrics/BUILD.gn
@@ -240,6 +240,12 @@ if (!is_ios) {
   }
 }
 
+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
@@ -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" ]
+  }

[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.

 }