Vector should consult allocator about ideal size when choosing capacity.
<http://webkit.org/b/108410>
<rdar://problem/13124002>

Source/JavaScriptCore:

Patch by Filip Pizlo <fpizlo@apple.com> on 2013-01-30
Reviewed by Benjamin Poulain.

Remove assertion about Vector capacity that won't hold anymore since capacity()
may not be what you passed to reserveCapacity().

* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::CodeBlock):

Source/WTF:

Reviewed by Benjamin Poulain.

Added WTF::fastMallocGoodSize(), a workalike/wrapper for OS X's malloc_good_size().
It returns the actual size of the block that will get allocated for a given byte size.

Vector's internal buffer now checks with the allocator if the resulting allocation
could actually house more objects and updates its capacity to make use of the space.

* wtf/Deque.h:
(WTF::::expandCapacity):
* wtf/FastMalloc.cpp:
(WTF::fastMallocGoodSize):
* wtf/FastMalloc.h:
* wtf/Vector.h:
(WTF::VectorBufferBase::allocateBuffer):
(WTF::VectorBufferBase::tryAllocateBuffer):
(WTF::VectorBufferBase::reallocateBuffer):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141407 268f45cc-cd09-0410-ab3c-d52691b4dbfc