Add aligned_alloc to libc allocator shim.

third_party/vulkan_memory_allocator uses posix_memalign inside vma_aligned_alloc only when defined(__linux__) && defined(__GLIBCXX__) && !defined(_GLIBCXX_HAVE_ALIGNED_ALLOC). When building chrome on linux-rel (using libc), aligned_alloc will be used instead. Since libc allocator shim overrides free, freeing memory allocated by aligned_alloc causes crash.

Bug: 1121427
Change-Id: I4d6c34e493a685520bb0c561b1b1c6b16ceb38e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2392230Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Benoit L <lizeb@chromium.org>
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#807423}

base/allocator/allocator_shim_override_libc_symbols.h

@@ -40,6 +40,10 @@ SHIM_ALWAYS_EXPORT void* memalign(size_t align, size_t s) __THROW {
   return ShimMemalign(align, s, nullptr);
 }
 
+SHIM_ALWAYS_EXPORT void* aligned_alloc(size_t align, size_t s) __THROW {
+  return ShimMemalign(align, s, nullptr);
+}
+
 SHIM_ALWAYS_EXPORT void* valloc(size_t size) __THROW {
   return ShimValloc(size, nullptr);
 }