Bug 1344629 - Part 6: Rewrite unnecessary uses of nsLiteralString. r=dbaron

There's an antipattern where nsLiteralString is used as an unnecessary intermediary in converting from CharT* to CharT*,
e.g. CallAFunctionThatTakesACharPointer(NS_LITERAL_CSTRING("foo").get());
or
NS_NAMED_LITERAL_STRING(foo, "abc");
CallAFunctionThatTakesACharPointer(foo.get());

This patch rewrites the callsites that can be trivially changed to use char*/char16_t*.

I'd somewhat like to remove nsTLiteralString::get() altogether, but in code that's less straightforward than these examples, get() is useful enough to keep.

MozReview-Commit-ID: Kh1rUziVllo

dom/html/MediaDocument.cpp

@@ -418,8 +418,7 @@ MediaDocument::UpdateTitleAndCharset(const nsACString& aTypeStr,
     nsXPIDLString titleWithStatus;
     const nsPromiseFlatString& status = PromiseFlatString(aStatus);
     const char16_t *formatStrings[2] = {title.get(), status.get()};
-    NS_NAMED_LITERAL_STRING(fmtName, "TitleWithStatus");
-    mStringBundle->FormatStringFromName(fmtName.get(), formatStrings, 2,
+    mStringBundle->FormatStringFromName(u"TitleWithStatus", formatStrings, 2,
                                         getter_Copies(titleWithStatus));
     SetTitle(titleWithStatus);
   }