Stack sampling profiler: handle unloaded and unloading modules

base/profiler/stack_sampling_profiler.h

Index: base/profiler/stack_sampling_profiler.h
diff --git a/base/profiler/stack_sampling_profiler.h b/base/profiler/stack_sampling_profiler.h
index 9aa9c31d67afd31a12113f5caeeb1b53e3ae771e..e9b1804bbf282ee3cbc0d7764d306d6b563f4e41 100644
--- a/base/profiler/stack_sampling_profiler.h
+++ b/base/profiler/stack_sampling_profiler.h
@@ -20,6 +20,7 @@
 namespace base {
 
 class NativeStackSampler;
+class NativeStackSamplerTestDelegate;
 
 // StackSamplingProfiler periodically stops a thread to sample its stack, for
 // the purpose of collecting information about which code paths are
@@ -156,10 +157,15 @@ class BASE_EXPORT StackSamplingProfiler {
   // thread-safe callback implementation.
   using CompletedCallback = Callback<void(const CallStackProfiles&)>;
 
-  // Creates a profiler that sends completed profiles to |callback|.
+  // Creates a profiler that sends completed profiles to |callback|. The second
+  // constructor is for test purposes.

[brucedawson, 2015/10/30 00:15:59]

Wouldn't it be simpler to have test_delegate have a default value and just have
the one constructor?

[Mike Wittman, 2015/10/30 17:08:07]

I'm not sure. Although default arguments are permitted on constructors, using
separate functions is consistent with the rest of the code where they're
prohibited. This way probably looks less strange to the average reader who's
unfamiliar with the quirks of the style guide.

   StackSamplingProfiler(PlatformThreadId thread_id,
                         const SamplingParams& params,
                         const CompletedCallback& callback);
+  StackSamplingProfiler(PlatformThreadId thread_id,
+                        const SamplingParams& params,
+                        const CompletedCallback& callback,
+                        NativeStackSamplerTestDelegate* test_delegate);
   // Stops any profiling currently taking place before destroying the profiler.
   ~StackSamplingProfiler();
 
@@ -231,6 +237,9 @@ class BASE_EXPORT StackSamplingProfiler {
 
   const CompletedCallback completed_callback_;
 
+  // Stored until it can be passed to the NativeStackSampler created in Start().
+  NativeStackSamplerTestDelegate* const test_delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(StackSamplingProfiler);
 };