Add method Vector::shrinkToReasonableCapacity()

Source/wtf/Vector.h

Index: Source/wtf/Vector.h
diff --git a/Source/wtf/Vector.h b/Source/wtf/Vector.h
index ab18fe5fe421fae435d5627c5adcc6542d981021..cb1b4adb54e22ecd589687ae3f698286f7ccfc2f 100644
--- a/Source/wtf/Vector.h
+++ b/Source/wtf/Vector.h
@@ -675,6 +675,11 @@ static const size_t kInitialVectorSize = WTF_VECTOR_INITIAL_SIZE;
         void reserveCapacity(size_t newCapacity);
         void reserveInitialCapacity(size_t initialCapacity);
         void shrinkToFit() { shrinkCapacity(size()); }
+        void shrinkToReasonableCapacity()

[Mikhail, 2014/04/16 08:29:14]

Is this method supposed to be called so frequently that it's worth adding it to
Vector class? The client can always have it as a free function

void shrinkToReasonableCapacity(Vector& vector)
{
 ...
}

[danakj, 2014/04/16 15:55:06]

shrinkCapacity() is currently private, so this needs to be added, or something
else needs to be made public.

+        {
+            if (UNLIKELY(size() * 2 < capacity()))

[abarth-chromium, 2014/04/16 00:58:38]

Sorry to leave a drive-by comment, but please don't add UNLIKELY macros unless
you have a benchmark (even a microbenchmark) that shows the win.  These macros
rarely make any measurable difference.

[ostap, 2014/04/16 16:11:02]

Thanks.
I tested. It really makes no difference.

+                shrinkCapacity(size() + size() / 4 + 1);
+        }
 
         void clear() { shrinkCapacity(0); }