Bug 1430317: Add memory reporter to show basic information about active WebExtensions. r=erahm

MozReview-Commit-ID: FR8F30bhhA4

toolkit/components/extensions/ExtensionPolicyService.cpp

@@ -9,6 +9,7 @@
 
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/ResultExtensions.h"
 #include "mozilla/Services.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/ContentParent.h"
@@ -67,6 +68,7 @@ ExtensionPolicyService::GetSingleton()
 
   if (MOZ_UNLIKELY(!sExtensionPolicyService)) {
     sExtensionPolicyService = new ExtensionPolicyService();
+    RegisterWeakMemoryReporter(sExtensionPolicyService);
     ClearOnShutdown(&sExtensionPolicyService);
   }
   return *sExtensionPolicyService.get();
@@ -82,6 +84,11 @@ ExtensionPolicyService::ExtensionPolicyService()
   RegisterObservers();
 }
 
+ExtensionPolicyService::~ExtensionPolicyService()
+{
+  UnregisterWeakMemoryReporter(this);
+}
+
 bool
 ExtensionPolicyService::UseRemoteExtensions() const
 {
@@ -174,6 +181,45 @@ ExtensionPolicyService::DefaultCSP(nsAString& aDefaultCSP) const
 }
 
 
+/*****************************************************************************
+ * nsIMemoryReporter
+ *****************************************************************************/
+
+NS_IMETHODIMP
+ExtensionPolicyService::CollectReports(nsIHandleReportCallback* aHandleReport,
+                                       nsISupports* aData, bool aAnonymize)
+{
+  for (auto iter = mExtensions.Iter(); !iter.Done(); iter.Next()) {
+    auto& ext = iter.Data();
+
+    nsAtomCString id(ext->Id());
+
+    NS_ConvertUTF16toUTF8 name(ext->Name());
+    name.ReplaceSubstring("\"", "");
+    name.ReplaceSubstring("\\", "");
+
+    nsString url;
+    MOZ_TRY_VAR(url, ext->GetURL(NS_LITERAL_STRING("")));
+
+    nsPrintfCString desc("Extension(id=%s, name=\"%s\", baseURL=%s)",
+                         id.get(), name.get(),
+                         NS_ConvertUTF16toUTF8(url).get());
+    desc.ReplaceChar('/', '\\');
+
+    nsCString path("extensions/");
+    path.Append(desc);
+
+    aHandleReport->Callback(
+      EmptyCString(), path,
+      KIND_NONHEAP, UNITS_COUNT, 1,
+      NS_LITERAL_CSTRING("WebExtensions that are active in this session"),
+      aData);
+  }
+
+  return NS_OK;
+}
+
+
 /*****************************************************************************
  * Content script management
  *****************************************************************************/