Reduce boilerplace for common pattern to return MaybeHandle.

src/uri.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/uri.h"
 
 #include "src/char-predicates-inl.h"
 #include "src/handles.h"
 #include "src/isolate-inl.h"
 #include "src/list.h"
@@ skipping 71 matching lines @@
   uint8_t y = (cc2 >> 6) & 0xF;
   uint8_t z = cc2 & 63;
   AddHexEncodedToBuffer((u >> 2) + 240, buffer);
   AddHexEncodedToBuffer((((u & 3) << 4) | w) + 128, buffer);
   AddHexEncodedToBuffer(((x << 4) | y) + 128, buffer);
   AddHexEncodedToBuffer(z + 128, buffer);
 }
 
 }  // anonymous namespace
 
-Object* Uri::Encode(Isolate* isolate, Handle<String> uri, bool is_uri) {
+MaybeHandle<String> Uri::Encode(Isolate* isolate, Handle<String> uri,
+                                bool is_uri) {
   uri = String::Flatten(uri);
   int uri_length = uri->length();
   List<uint8_t> buffer(uri_length);
 
   {
     DisallowHeapAllocation no_gc;
     String::FlatContent uri_content = uri->GetFlatContent();
 
     for (int k = 0; k < uri_length; k++) {
       uc16 cc1 = uri_content.Get(k);
@@ skipping 10 matching lines @@
         if (IsUnescapePredicateInUriComponent(cc1) ||
             (is_uri && IsUriSeparator(cc1))) {
           buffer.Add(cc1);
         } else {
           EncodeSingle(cc1, &buffer);
         }
         continue;
       }
 
       AllowHeapAllocation allocate_error_and_return;
-      THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewURIError());
+      THROW_NEW_ERROR(isolate, NewURIError(), String);
     }
   }
 
-  Handle<String> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result,
-      isolate->factory()->NewStringFromOneByte(buffer.ToConstVector()));
-  return *result;
+  return isolate->factory()->NewStringFromOneByte(buffer.ToConstVector());
 }
 
 }  // namespace internal
 }  // namespace v8