Issue #2692 - Part 6: Don't #include js/SourceBufferHolder.h in jsapi.h.

Instead, require users to do so. This is a minor translation-unit size
improvement for anyone who never has to use SourceBufferHolder other than
by reference.

js/src/frontend/BytecodeCompiler.cpp

@@ -16,6 +16,7 @@
 #include "frontend/FoldConstants.h"
 #include "frontend/NameFunctions.h"
 #include "frontend/Parser.h"
+#include "js/SourceBufferHolder.h"
 #include "vm/GlobalObject.h"
 #include "vm/TraceLogging.h"
 #include "wasm/AsmJS.h"
@@ -27,9 +28,12 @@
 
 using namespace js;
 using namespace js::frontend;
+
 using mozilla::Maybe;
 using mozilla::Nothing;
 
+using JS::SourceBufferHolder;
+
 class MOZ_STACK_CLASS AutoCompilationTraceLogger
 {
   public: