Fix leaks in exensions_unittests after enabling Oilpan

extensions/renderer/module_system_test.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/module_system_test.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <string>
 #include <utility>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/strings/string_piece.h"
 #include "extensions/common/extension_paths.h"
 #include "extensions/renderer/logging_native_handler.h"
 #include "extensions/renderer/object_backed_native_handler.h"
 #include "extensions/renderer/safe_builtins.h"
 #include "extensions/renderer/utils_native_handler.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
 #include "ui/base/resource/resource_bundle.h"
 
 namespace extensions {
 namespace {
 
 class FailsOnException : public ModuleSystem::ExceptionHandler {
  public:
   FailsOnException() : ModuleSystem::ExceptionHandler(nullptr) {}
   void HandleUncaughtException(const v8::TryCatch& try_catch) override {
     FAIL() << "Uncaught exception: " << CreateExceptionString(try_catch);
@@ skipping 198 matching lines @@
   env_.reset();
   v8::HeapStatistics stats;
   isolate_->GetHeapStatistics(&stats);
   size_t old_heap_size = 0;
   // Run the GC until the heap size reaches a steady state to ensure that
   // all the garbage is collected.
   while (stats.used_heap_size() != old_heap_size) {
     old_heap_size = stats.used_heap_size();
     isolate_->RequestGarbageCollectionForTesting(
         v8::Isolate::kFullGarbageCollection);
+    blink::WebHeap::collectAllGarbageForTesting();

[sof, 2016/01/26 06:09:43]

The v8 major GC will trigger Oilpan GCs also, so unclear if this extra round
will make a difference.

[sof, 2016/01/26 08:05:44]

https://build.chromium.org/p/chromium.memory.fyi/builders/Linux%20Tests%20(va...
shows that it didn't.

Should we force a GC with collectGarbageForTesting() instead? (I cannot
reproduce these leaks locally with memcheck, btw.)

[haraken, 2016/01/26 08:26:40]

Doesn't collectAllGarbage always collect more objects than collectGarbage?

     isolate_->GetHeapStatistics(&stats);
   }
 }
 
 scoped_ptr<ModuleSystemTestEnvironment> ModuleSystemTest::CreateEnvironment() {
   return make_scoped_ptr(new ModuleSystemTestEnvironment(isolate_));
 }
 
 void ModuleSystemTest::ExpectNoAssertionsMade() {
   should_assertions_be_made_ = false;
 }
 
 void ModuleSystemTest::RunResolvedPromises() {
   isolate_->RunMicrotasks();
 }
 
 }  // namespace extensions