Enable TCMalloc on Linux by default.

chrome/app/chrome_exe_main_gtk.cc

 // Copyright (c) 2008 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 "base/at_exit.h"
 #include "base/process_util.h"
 
 // The entry point for all invocations of Chromium, browser and renderer. On
 // windows, this does nothing but load chrome.dll and invoke its entry point in
 // order to make it easy to update the app from GoogleUpdate. We don't need
 // that extra layer with on linux.
 //
 // TODO(tc): This is similar to chrome_exe_main.mm.  After it's more clear what
 // needs to go here, we should evaluate whether or not to merge this file with
 // chrome_exe_main.mm.
 
 extern "C" {
 int ChromeMain(int argc, const char** argv);
+
+#if defined(LINUX_USE_TCMALLOC)
+
+int tc_set_new_mode(int mode);
+
+#endif  // defined(LINUX_USE_TCMALLOC)
+
 }
 
 int main(int argc, const char** argv) {
   base::EnableTerminationOnHeapCorruption();
   base::EnableTerminationOnOutOfMemory();
 
+  // NOTE(willchan): One might ask why this call is done here rather than in
+  // process_util_linux.cc with the definition of
+  // EnableTerminationOnOutOfMemory().  That's because base shouldn't have a
+  // dependency on TCMalloc.  Really, we ought to have our allocator shim code
+  // implement this EnableTerminationOnOutOfMemory() function.  Whateverz.  This
+  // works for now.
+#if defined(LINUX_USE_TCMALLOC)
+  // For tcmalloc, we need to tell it to behave like new.
+  tc_set_new_mode(1);
+#endif
+
   // The exit manager is in charge of calling the dtors of singletons.
   // Win has one here, but we assert with multiples from BrowserMain() if we
   // keep it.
   // base::AtExitManager exit_manager;
 
 #if defined(GOOGLE_CHROME_BUILD)
   // TODO(tc): init crash reporter
 #endif
 
   return ChromeMain(argc, argv);
 }