Remove old/unused atomicops code

base/allocator/BUILD.gn

Index: base/allocator/BUILD.gn
diff --git a/base/allocator/BUILD.gn b/base/allocator/BUILD.gn
index a07a356e5d85a204d5f4bd3e3850f50b0e3ff43c..c42de1a01a38900bdbf8e23029ffeb9b78441c61 100644
--- a/base/allocator/BUILD.gn
+++ b/base/allocator/BUILD.gn
@@ -63,6 +63,17 @@ if (use_allocator == "tcmalloc") {
       "$tcmalloc_dir/src/base/abort.cc",
       "$tcmalloc_dir/src/base/abort.h",
       "$tcmalloc_dir/src/base/arm_instruction_set_select.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-arm-generic.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-arm-v6plus.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-linuxppc.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-macosx.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-windows.h",
+      "$tcmalloc_dir/src/base/atomicops-internals-x86.cc",
+      "$tcmalloc_dir/src/base/atomicops-internals-x86.h",

[Nico, 2015/07/01 18:49:07]

Would the generic atomics work for tcmalloc too?

[Sam Clegg, 2015/07/01 18:52:58]

Sure.  Makes sense not to have multiple copies of such things,
 but that should be a separate change.

Also, the tcmalloc version we use here is many years old.  It could use a
refresh, but all the refresh instructions are still svn based.

[Nico, 2015/07/01 18:55:08]

Oh yeah, totally.
It's not just old, it's fairly different. From what I understand, there's now 3
tcmalloc versions, all pretty different:
1. Open-source tcmalloc
2. Google-internal tcmalloc, as far as I know that's not synced with open-source
tcmalloc at all
3. Chromium tcmalloc

:-/

+      "$tcmalloc_dir/src/base/atomicops.h",
+      "$tcmalloc_dir/src/base/basictypes.h",
+      "$tcmalloc_dir/src/base/commandlineflags.h",
+      "$tcmalloc_dir/src/base/cycleclock.h",
 
       # We don't list dynamic_annotations.c since its copy is already
       # present in the dynamic_annotations target.