Use handles in API object hooks where possible, bug 750733. r=billm

caps/include/nsScriptSecurityManager.h

caps/src/nsScriptSecurityManager.cpp

content/canvas/src/CustomQS_Canvas2D.h

content/xbl/src/nsXBLBinding.cpp

content/xbl/src/nsXBLDocumentInfo.cpp

content/xul/document/src/nsXULPrototypeDocument.cpp

dom/base/nsDOMClassInfo.cpp

dom/base/nsDOMClassInfo.h

dom/base/nsDOMWindowUtils.cpp

dom/bindings/Codegen.py

dom/plugins/base/nsJSNPRuntime.cpp

dom/workers/ChromeWorkerScope.cpp

dom/workers/Events.cpp

dom/workers/Exceptions.cpp

dom/workers/File.cpp

dom/workers/ImageData.cpp

dom/workers/Location.cpp

dom/workers/Navigator.cpp

dom/workers/RuntimeService.cpp

dom/workers/Worker.cpp