Inspector: Skip a copy/widening of the injected script source.

This reduces the number of times this string is copied from two to one.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I8680cfc1ef1d6c2cfd3bc4970fe698bb904ce328
Reviewed-on: https://chromium-review.googlesource.com/652591Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47861}

src/inspector/injected-script.cc

@@ -272,8 +272,8 @@ std::unique_ptr<InjectedScript> InjectedScript::create(
   // The function is expected
   // to create and configure InjectedScript instance that is going to be used by
   // the inspector.
-  String16 injectedScriptSource(
-      reinterpret_cast<const char*>(InjectedScriptSource_js),
+  StringView injectedScriptSource(
+      reinterpret_cast<const uint8_t*>(InjectedScriptSource_js),
       sizeof(InjectedScriptSource_js));
   v8::Local<v8::Value> value;
   if (!inspectedContext->inspector()