Add use_allocator instead of linux_use_tcmalloc to switch the allocator.

ash/ash.gyp

Index: ash/ash.gyp
diff --git a/ash/ash.gyp b/ash/ash.gyp
index 6654328789be6511cd90df00fb5e4a43e45139b4..f970de599061102cfeef8785c50fef617c2cdaef 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -1025,7 +1025,8 @@
             ['exclude', 'display/resolution_notification_controller_unittest.cc'],
           ],
         }],
-        ['OS=="linux" and component=="shared_library" and linux_use_tcmalloc==1', {
+        # TODO(dmikurube): Kill linux_use_tcmalloc. http://crbug.com/345554
+        ['OS=="linux" and component=="shared_library" and ((use_allocator!="none" and use_allocator!="see_use_tcmalloc") or (use_allocator=="see_use_tcmalloc" and linux_use_tcmalloc==1))', {
           'dependencies': [
             '<(DEPTH)/base/allocator/allocator.gyp:allocator',
           ],