[v8] Remove deprecated StreamedSource API use

Use the StreamedSource constructor taking a unique_ptr<SourceStream> rather
than the raw pointer version, which is less clear about ownership and so is
deprecated.

Change-Id: I8d95d8049b60925ea11f16249ba18ba5044908d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899848
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712626}

third_party/blink/renderer/bindings/core/v8/script_streamer.cc

@@ -435,11 +435,12 @@ bool ScriptStreamer::TryStartStreaming(
 
   DCHECK(!stream_);
   DCHECK(!source_);
-  stream_ = new SourceStream;
+  auto stream_ptr = std::make_unique<SourceStream>();
+  stream_ = stream_ptr.get();
   // |source_| takes ownership of |stream_|, and will keep |stream_| alive until
   // |source_| is destructed.
-  source_ =
-      std::make_unique<v8::ScriptCompiler::StreamedSource>(stream_, encoding_);
+  source_ = std::make_unique<v8::ScriptCompiler::StreamedSource>(
+      std::move(stream_ptr), encoding_);
 
   std::unique_ptr<v8::ScriptCompiler::ScriptStreamingTask>
       script_streaming_task(