[wasm] GrowMemory should use array_buffer_allocator instead of realloc.

src/runtime/runtime-wasm.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/assembler.h"
 #include "src/compiler/wasm-compiler.h"
 #include "src/conversions.h"
@@ skipping 68 matching lines @@
     // If the old memory was zero-sized, we should have been in the
     // "undefined" case above.
     DCHECK_NOT_NULL(old_mem_start);
     DCHECK_NE(0, old_size);
 
     new_size = old_size + delta_pages * wasm::WasmModule::kPageSize;
     if (new_size >
         wasm::WasmModule::kMaxMemPages * wasm::WasmModule::kPageSize) {
       return *isolate->factory()->NewNumberFromInt(-1);
     }
-    new_mem_start = static_cast<Address>(realloc(old_mem_start, new_size));
+    new_mem_start =
+        static_cast<Address>(isolate->array_buffer_allocator()->Allocate(
+            static_cast<uint32_t>(new_size)));
     if (new_mem_start == NULL) {
       return *isolate->factory()->NewNumberFromInt(-1);
     }
-    old_buffer->set_is_external(true);
-    isolate->heap()->UnregisterArrayBuffer(*old_buffer);
-    // Zero initializing uninitialized memory from realloc
-    memset(new_mem_start + old_size, 0, new_size - old_size);
+#if DEBUG
+    // Double check the API allocator actually zero-initialized the memory.
+    for (size_t i = old_size; i < new_size; i++) {
+      DCHECK_EQ(0, new_mem_start[i]);
+    }
+#endif
+    // Copy contents of the old buffer to the new buffer
+    memcpy(new_mem_start, old_mem_start, old_size);
   }
 
   Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
   JSArrayBuffer::Setup(buffer, isolate, false, new_mem_start, new_size);
   buffer->set_is_neuterable(false);
 
   // Set new buffer to be wasm memory
   module_object->SetInternalField(kWasmMemArrayBuffer, *buffer);
-
   CHECK(wasm::UpdateWasmModuleMemory(module_object, old_mem_start,
                                      new_mem_start, old_size, new_size));
 
   return *isolate->factory()->NewNumberFromInt(old_size /
                                                wasm::WasmModule::kPageSize);
 }
 
 RUNTIME_FUNCTION(Runtime_WasmThrowTypeError) {
   HandleScope scope(isolate);
   DCHECK_EQ(0, args.length());
   THROW_NEW_ERROR_RETURN_FAILURE(
       isolate, NewTypeError(MessageTemplate::kWasmTrapTypeError));
 }
 }  // namespace internal
 }  // namespace v8