Bug 1474636 - Report memory used by nsMemoryReporterManager. r=njn

This adds reporting of nsMemoryReporterManager's internals. Currently we just
report the weak and strong ref hashtables which have shown up in DMD reports.

The new entry is '/explicit/memory-reporter-manager'.

--HG--
extra : rebase_source : ab785a96a0dd52a4e09718bea015363cdf2c9c8a
extra : source : 86ba30c70a27ab73f096fe88d2005aad8470ee05

xpcom/base/nsMemoryReporterManager.cpp

@@ -1521,7 +1521,7 @@ NS_IMPL_ISUPPORTS(DMDReporter, nsIMemoryReporter)
  ** nsMemoryReporterManager implementation
  **/
 
-NS_IMPL_ISUPPORTS(nsMemoryReporterManager, nsIMemoryReporterManager)
+NS_IMPL_ISUPPORTS(nsMemoryReporterManager, nsIMemoryReporterManager, nsIMemoryReporter)
 
 NS_IMETHODIMP
 nsMemoryReporterManager::Init()
@@ -1614,6 +1614,9 @@ nsMemoryReporterManager::Init()
   nsMemoryInfoDumper::Initialize();
 #endif
 
+  // Report our own memory usage as well.
+  RegisterWeakReporter(this);
+
   return NS_OK;
 }
 
@@ -1641,6 +1644,22 @@ nsMemoryReporterManager::~nsMemoryReporterManager()
   NS_ASSERTION(!mSavedWeakReporters, "failed to restore weak reporters");
 }
 
+NS_IMETHODIMP
+nsMemoryReporterManager::CollectReports(nsIHandleReportCallback* aHandleReport,
+                                        nsISupports* aData, bool aAnonymize)
+{
+  size_t n = MallocSizeOf(this);
+  n += mStrongReporters->ShallowSizeOfIncludingThis(MallocSizeOf);
+  n += mWeakReporters->ShallowSizeOfIncludingThis(MallocSizeOf);
+
+  MOZ_COLLECT_REPORT(
+    "explicit/memory-reporter-manager", KIND_HEAP, UNITS_BYTES,
+    n,
+    "Memory used by the memory reporter infrastructure.");
+
+  return NS_OK;
+}
+
 #ifdef DEBUG_CHILD_PROCESS_MEMORY_REPORTING
 #define MEMORY_REPORTING_LOG(format, ...) \
   printf_stderr("++++ MEMORY REPORTING: " format, ##__VA_ARGS__);

xpcom/base/nsMemoryReporterManager.h

@@ -25,13 +25,17 @@ class MemoryReport;
 
 class nsITimer;
 
-class nsMemoryReporterManager final : public nsIMemoryReporterManager
+class nsMemoryReporterManager final : public nsIMemoryReporterManager,
+                                      public nsIMemoryReporter
 {
   virtual ~nsMemoryReporterManager();
 
 public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSIMEMORYREPORTERMANAGER
+  NS_DECL_NSIMEMORYREPORTER
+
+  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf)
 
   nsMemoryReporterManager();