[PartitionAlloc] Disable the thread cache for malloc() on Windows.

This breaks compilation, disable it temporarily.

Bug: 998048
Change-Id: Ic55d9eed165742a97389a225abe139a5c7fb8be5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472357
Auto-Submit: Benoit L <lizeb@chromium.org>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817344}

base/allocator/partition_allocator/partition_alloc.cc

@@ -320,7 +320,10 @@ void PartitionRoot<thread_safe>::Init(PartitionOptions opts) {
   // this operation is idempotent, so there is no harm.
   InitBucketIndexLookup(this);
 
-#if !defined(PA_THREAD_CACHE_SUPPORTED)
+  // Temporarily disabled for PartitionAlloc-Everywhere builds on Windows, as it
+  // breaks the build.
+#if !defined(PA_THREAD_CACHE_SUPPORTED) || \
+    (defined(OS_WIN) && BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC))
   // TLS in ThreadCache not supported on other OSes.
   with_thread_cache = false;
 #else
@@ -329,7 +332,8 @@ void PartitionRoot<thread_safe>::Init(PartitionOptions opts) {
 
   if (with_thread_cache)
     internal::ThreadCache::Init(this);
-#endif  // !defined(OS_POSIX)
+#endif  // !defined(PA_THREAD_CACHE_SUPPORTED) || \
+        // (defined(OS_WIN) && BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC))
 
   initialized = true;
 }