Make static API getters inlineable.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index af86f44ad2588677c3140270b2c0512c6247799c..83f69ffdc6ea980ecd6ac652f63fd7a723f804de 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1418,6 +1418,11 @@ class Heap {
     kRootListLength
   };
 
+  STATIC_CHECK(kUndefinedValueRootIndex == Internals::kUndefinedValueRootIndex);
+  STATIC_CHECK(kNullValueRootIndex == Internals::kNullValueRootIndex);
+  STATIC_CHECK(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
+  STATIC_CHECK(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
+
   MUST_USE_RESULT MaybeObject* NumberToString(
       Object* number, bool check_number_string_cache = true);
   MUST_USE_RESULT MaybeObject* Uint32ToString(
@@ -1612,6 +1617,8 @@ class Heap {
   // more expedient to get at the isolate directly from within Heap methods.
   Isolate* isolate_;
 
+  Object* roots_[kRootListLength];
+
   intptr_t code_range_size_;
   int reserved_semispace_size_;
   int max_semispace_size_;
@@ -1727,8 +1734,6 @@ class Heap {
   // last GC.
   int old_gen_exhausted_;
 
-  Object* roots_[kRootListLength];
-
   Object* global_contexts_list_;
 
   StoreBufferRebuilder store_buffer_rebuilder_;