Add a benchmarking_extension API to call TCMalloc's HeapProfilerDump().

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index f323a27fcc26002d9fd5e5c4721afc7be49e596c..fb4d9c3cda65e137d8d1e9d97500270aa6b50083 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -45,6 +45,7 @@
 #include "chrome/renderer/extensions/resource_request_policy.h"
 #include "chrome/renderer/external_extension.h"
 #include "chrome/renderer/loadtimes_extension_bindings.h"
+#include "chrome/renderer/memory_benchmarking_extension.h"
 #include "chrome/renderer/net/renderer_net_predictor.h"
 #include "chrome/renderer/one_click_signin_agent.h"
 #include "chrome/renderer/page_click_tracker.h"
@@ -216,8 +217,11 @@ void ChromeContentRendererClient::RenderThreadStarted() {
   thread->RegisterExtension(extensions_v8::SearchBoxExtension::Get());
 
   CommandLine* command_line = CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kEnableBenchmarking))
+  if (command_line->HasSwitch(switches::kEnableBenchmarking)) {
     thread->RegisterExtension(extensions_v8::BenchmarkingExtension::Get());
+    thread->RegisterExtension(
+        extensions_v8::MemoryBenchmarkingExtension::Get());
+  }
 
   if (command_line->HasSwitch(switches::kPlaybackMode) ||
       command_line->HasSwitch(switches::kRecordMode) ||