fuchsia: base_unittests (mostly) compiling

base/trace_event/malloc_dump_provider.cc

Index: base/trace_event/malloc_dump_provider.cc
diff --git a/base/trace_event/malloc_dump_provider.cc b/base/trace_event/malloc_dump_provider.cc
index 047f2c336d5c6295086316b12f883811ab9f2b0c..7b3831c08d64a723d3773ba754708a3121c69e49 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -242,6 +242,8 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
   resident_size = main_heap_info.committed_size;
   allocated_objects_size = main_heap_info.allocated_size;
   allocated_objects_count = main_heap_info.block_count;
+#elif defined(OS_FUCHSIA)
+// TODO(fuchsia): Port, see https://crbug.com/706592.
 #else
   struct mallinfo info = mallinfo();
   DCHECK_GE(info.arena + info.hblkhd, info.uordblks);