Bug 1600644 - Don't count ActivePS::mProfileBuffer's own size twice - r=canaltinova

In bug 1587332, ActivePS::mProfileBuffer was changed from
`const UniquePtr<ProfileBuffer>` to just `ProfileBuffer`, so its own object size
is now counted as part of `sizeof(ActivePS)`, and we should only count its
dependencies with `SizeOfExcludingThis`.

Differential Revision: https://phabricator.services.mozilla.com/D58288

--HG--
extra : moz-landing-system : lando

mozglue/baseprofiler/core/platform.cpp

@@ -622,7 +622,7 @@ class ActivePS {
 
     size_t n = aMallocSizeOf(sInstance);
 
-    n += sInstance->mProfileBuffer.SizeOfIncludingThis(aMallocSizeOf);
+    n += sInstance->mProfileBuffer.SizeOfExcludingThis(aMallocSizeOf);
 
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:

tools/profiler/core/platform.cpp

@@ -780,7 +780,7 @@ class ActivePS {
 
     size_t n = aMallocSizeOf(sInstance);
 
-    n += sInstance->mProfileBuffer.SizeOfIncludingThis(aMallocSizeOf);
+    n += sInstance->mProfileBuffer.SizeOfExcludingThis(aMallocSizeOf);
 
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile: