Route calls to tcmalloc MallocExtension through allocator agnostic interface

content/app/content_main_runner.cc

Index: content/app/content_main_runner.cc
diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index 4f286fd71fa58df306c48459f8ee4a46d4043585..6af508c4b1bc66764bcc44f251544c445d0eff40 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -4,6 +4,7 @@
 
 #include "content/public/app/content_main_runner.h"
 
+#include "base/allocator/allocator_extension.h"
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
@@ -37,6 +38,10 @@
 #include "ui/base/win/dpi.h"
 #include "webkit/glue/webkit_glue.h"
 
+#if defined(USE_TCMALLOC)
+#include "third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h"
+#endif
+
 #if defined(OS_WIN)
 #include <atlbase.h>
 #include <atlapp.h>
@@ -314,6 +319,17 @@ class ContentMainRunnerImpl : public content::ContentMainRunner {
       Shutdown();
   }
 
+#if defined(USE_TCMALLOC)
+static void get_stats_thunk(char* buffer, int buffer_length) {

[jam, 2012/04/26 21:28:20]

nit: chrome style is GetStatsThunk. also below

+    MallocExtension::instance()->GetStats(buffer, buffer_length);

[jam, 2012/04/26 21:28:20]

nit: 2 spaces.. also below

+}
+
+static void release_free_memory_thunk() {
+    MallocExtension::instance()->ReleaseFreeMemory();
+}
+#endif
+
+
 #if defined(OS_WIN)
   virtual int Initialize(HINSTANCE instance,
                          sandbox::SandboxInterfaceInfo* sandbox_info,
@@ -345,6 +361,12 @@ class ContentMainRunnerImpl : public content::ContentMainRunner {
     tc_set_new_mode(1);
 #endif
 
+    // On windows, we've already set these thunks up in _heap_init()
+#if !defined(OS_WIN) && defined(USE_TCMALLOC)

[jam, 2012/04/26 21:28:20]

nit: if you don't want windows, then move this up inside the second part of the
ifdef above

+    base::allocator::SetGetStatsFunction(get_stats_thunk);
+    base::allocator::SetReleaseFreeMemoryFunction(release_free_memory_thunk);
+#endif
+
 #if !defined(OS_ANDROID)
     // Set C library locale to make sure CommandLine can parse argument values
     // in correct encoding.