Add a browser test for performance.memory

This CL adds a browsertest to ensure that performance.memory is not bucketized
when sites are isolated.

Change-Id: Icd6b1ee73a5f4e03f9e27c5f60d0cf741f66ba5c
Reviewed-on: https://chromium-review.googlesource.com/1106306Reviewed-by: Charlie Reis <creis@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570853}

content/browser/performance_memory_browsertest.cc

+// Copyright 2018 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/frame_host/frame_tree.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test_utils.h"
+#include "content/public/test/content_browser_test.h"
+#include "content/public/test/content_browser_test_utils.h"
+#include "content/shell/browser/shell.h"
+#include "content/test/content_browser_test_utils_internal.h"
+#include "net/dns/mock_host_resolver.h"
+
+namespace content {
+
+class PerformanceMemoryBrowserTest : public ContentBrowserTest {
+ public:
+  PerformanceMemoryBrowserTest() {}
+
+ protected:
+  void SetUpOnMainThread() override {
+    host_resolver()->AddRule("*", "127.0.0.1");
+    SetupCrossSiteRedirector(embedded_test_server());
+    ASSERT_TRUE(embedded_test_server()->Start());
+  }
+};
+
+// Verify that performance.memory is not bucketized when sites are isolated for
+// testing, and that it is bucketized when they are not.
+IN_PROC_BROWSER_TEST_F(PerformanceMemoryBrowserTest, PerformanceMemory) {
+  GURL main_url(embedded_test_server()->GetURL("a.com", "/title1.html"));
+  EXPECT_TRUE(NavigateToURL(shell(), main_url));
+
+  WebContents* contents = shell()->web_contents();
+  FrameTreeNode* root =
+      static_cast<WebContentsImpl*>(contents)->GetFrameTree()->root();
+  int usedJSHeapSize = -1;
+  EXPECT_TRUE(ExecuteScriptAndExtractInt(
+      root,
+      "window.domAutomationController.send(performance.memory.usedJSHeapSize);",
+      &usedJSHeapSize));
+
+  EXPECT_GE(usedJSHeapSize, 0);
+  // There is no explicit way to check if the memory values are bucketized or
+  // not. As in third_party/blink/renderer/core/timing/memory_info_test.cc,
+  // check that the value mod 100000 is non-zero to verify that it is
+  // not bucketized. This should be the case when the renderer process is locked
+  // to a site (i.e. scheme plus eTLD+1).
+  if (AreAllSitesIsolatedForTesting())
+    EXPECT_NE(0, usedJSHeapSize % 100000);
+  else
+    EXPECT_EQ(0, usedJSHeapSize % 100000);
+}
+
+}  // namespace content

content/test/BUILD.gn

@@ -786,6 +786,7 @@ test("content_browsertests") {
     "../browser/network_service_restart_browsertest.cc",
     "../browser/oop_browsertest.cc",
     "../browser/payments/payment_app_browsertest.cc",
+    "../browser/performance_memory_browsertest.cc",
     "../browser/pointer_lock_browsertest.cc",
     "../browser/pointer_lock_browsertest.h",
     "../browser/pointer_lock_browsertest_mac.mm",