Reland of [tracing] Dump child processes' memory metrics in browser

chrome/test/base/tracing_browsertest.cc

 // Copyright (c) 2012 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 "chrome/test/base/tracing.h"
 
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 43 matching lines @@
         ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
     ASSERT_NO_FATAL_FAILURE(ExecuteJavascriptOnCurrentTab());
 
     // Begin tracing and watch for multiple periodic dump trace events.
     std::string event_name = base::trace_event::MemoryDumpTypeToString(
         MemoryDumpType::PERIODIC_INTERVAL);
     ASSERT_TRUE(BeginTracingWithWatch(MemoryDumpManager::kTraceCategory,
                                       MemoryDumpManager::kTraceCategory,
                                       event_name, 10));
 
-    GURL url2("chrome://credits/");
+    // Create and destroy renderers while tracing is enabled.
+    GURL url2("chrome://credits");
     ui_test_utils::NavigateToURLWithDisposition(
         browser(), url2, NEW_FOREGROUND_TAB,
         ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
     ASSERT_NO_FATAL_FAILURE(ExecuteJavascriptOnCurrentTab());
 
+    // Close the current tab.
+    browser()->tab_strip_model()->CloseSelectedTabs();
+
+    GURL url3("chrome://settings");
+    ui_test_utils::NavigateToURLWithDisposition(
+        browser(), url3, CURRENT_TAB,
+        ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+    ASSERT_NO_FATAL_FAILURE(ExecuteJavascriptOnCurrentTab());
+
     EXPECT_TRUE(WaitForWatchEvent(no_timeout));
     ASSERT_TRUE(EndTracing(&json_events));
 
     // Expect the basic memory dumps to be present in the trace.
     EXPECT_NE(std::string::npos, json_events.find("process_totals"));
 
     EXPECT_NE(std::string::npos, json_events.find("v8"));
     EXPECT_NE(std::string::npos, json_events.find("blink_gc"));
   }
 };
@@ skipping 77 matching lines @@
 IN_PROC_BROWSER_TEST_F(TracingBrowserTest, TestMemoryInfra) {
   PerformDumpMemoryTestActions();
 }
 
 // Single-process mode.
 IN_PROC_BROWSER_TEST_F(SingleProcessTracingBrowserTest, TestMemoryInfra) {
   PerformDumpMemoryTestActions();
 }
 
 }  // namespace