Linux: Make TCMalloc override ptmalloc hooks.

Linux: Make TCMalloc override ptmalloc hooks.
Certain libraries still seem to fall through to ptmalloc.  At least one cause seems to be because some libraries dynamically load other libraries via dlopen() invoked with RTLD_DEEPBIND.  Therefore, we override ptmalloc's hooks to pass through to TCMalloc.  This is suboptimal since it adds an extra function call per malloc()/realloc()/free()/memalign() invocation, but it should catch all cases where the library does not correctly allow for malloc implementation overrides.
BUG=38692
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=44975

[Lei Zhang, 2010-04-19 21:02:15]

Yes this works, but the change needs to go into the same spot in tcmalloc.cc
instead. It seems we have unforked tcmalloc_linux.cc in
base/allocator/allocator.gyp. We are not using third_party/tcmalloc/tcmalloc.gyp
at all for Chromium.

[willchan no longer on Chromium, 2010-04-19 22:17:47]

Updated to tcmalloc.cc.  Added glider to cc.

[Lei Zhang, 2010-04-19 22:24:58]

LGTM

FYI, this does not fix http://crbug.com/40974