Introduce MemoryCoordinatorProxy in base

content/browser/memory/memory_coordinator_browsertest.cc

 // Copyright 2016 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 "content/browser/memory/memory_coordinator.h"
 #include "content/browser/browser_main_loop.h"
 #include "content/public/common/content_features.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
 
 namespace content {
 
-namespace {
-
-void EnableForTesting() {
-  base::FeatureList::ClearInstanceForTesting();
-  std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
-  feature_list->InitializeFromCommandLine(features::kMemoryCoordinator.name,
-                                          "");
-  base::FeatureList::SetInstance(std::move(feature_list));
-}
-
-}  // namespace
-
 class MemoryCoordinatorTest : public ContentBrowserTest {
  public:
   MemoryCoordinatorTest() {}
 
   void SetUp() override {
-    EnableForTesting();
+    MemoryCoordinator::EnableFeaturesForTesting();
     ContentBrowserTest::SetUp();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MemoryCoordinatorTest);
 };
 
 // TODO(bashi): Enable this test on macos when MemoryMonitorMac is implemented.
 #if defined(OS_MACOSX)
 #define MAYBE_HandleAdded DISABLED_HandleAdded
 #else
 #define MAYBE_HandleAdded HandleAdded
 #endif
 IN_PROC_BROWSER_TEST_F(MemoryCoordinatorTest, MAYBE_HandleAdded) {
   GURL url = GetTestUrl("", "simple_page.html");
   NavigateToURL(shell(), url);
   EXPECT_EQ(1u, MemoryCoordinator::GetInstance()->NumChildrenForTesting());
 }
 
 }  // namespace content