Return MaybeHandle from NewExternalStringFrom*.

src/bootstrapper.cc

 // Copyright 2014 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 "bootstrapper.h"
 
 #include "accessors.h"
 #include "isolate-inl.h"
 #include "natives.h"
 #include "snapshot.h"
@@ skipping 35 matching lines @@
 Handle<String> Bootstrapper::NativesSourceLookup(int index) {
   ASSERT(0 <= index && index < Natives::GetBuiltinsCount());
   Heap* heap = isolate_->heap();
   if (heap->natives_source_cache()->get(index)->IsUndefined()) {
     // We can use external strings for the natives.
     Vector<const char> source = Natives::GetRawScriptSource(index);
     NativesExternalStringResource* resource =
         new NativesExternalStringResource(this,
                                           source.start(),
                                           source.length());
+    // We do not expect this to throw an exception. Change this if it does.
     Handle<String> source_code =
-        isolate_->factory()->NewExternalStringFromAscii(resource);
-    // We do not expect this to throw an exception. Change this if it does.
-    CHECK_NOT_EMPTY_HANDLE(isolate_, source_code);
+        isolate_->factory()->NewExternalStringFromAscii(
+            resource).ToHandleChecked();
     heap->natives_source_cache()->set(index, *source_code);
   }
   Handle<Object> cached_source(heap->natives_source_cache()->get(index),
                                isolate_);
   return Handle<String>::cast(cached_source);
 }
 
 
 void Bootstrapper::Initialize(bool create_heap_objects) {
   extensions_cache_.Initialize(isolate_, create_heap_objects);
@@ skipping 2242 matching lines @@
   extension_states->set_state(current, VISITED);
   v8::Extension* extension = current->extension();
   // Install the extension's dependencies
   for (int i = 0; i < extension->dependency_count(); i++) {
     if (!InstallExtension(isolate,
                           extension->dependencies()[i],
                           extension_states)) {
       return false;
     }
   }
+  // We do not expect this to throw an exception. Change this if it does.
   Handle<String> source_code =
-      isolate->factory()->NewExternalStringFromAscii(extension->source());
-  // We do not expect this to throw an exception. Change this if it does.
-  CHECK_NOT_EMPTY_HANDLE(isolate, source_code);
+      isolate->factory()->NewExternalStringFromAscii(
+          extension->source()).ToHandleChecked();
   bool result = CompileScriptCached(isolate,
                                     CStrVector(extension->name()),
                                     source_code,
                                     isolate->bootstrapper()->extensions_cache(),
                                     extension,
                                     Handle<Context>(isolate->context()),
                                     false);
   ASSERT(isolate->has_pending_exception() != result);
   if (!result) {
     // We print out the name of the extension that fail to install.
@@ skipping 385 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal