Fix some leaks associated with memory allocator
Fix some leaks associated with memory allocator

Use CFX_DefStore to only replace CFX_FixedStore, but not
CFX_StaticStore, since CFX_StaticStore has different behaviors.
CFX_StaticStore doesn't require its users to explicitly call free(),
it frees all the allocated memory during destruction. Use
CFX_DefStore to replace CFX_StaticStore would cause leaks.

Also remove two undeclared, but defined, functions.

BUG=pdfium:242

Review-Url: https://codereview.chromium.org/2328403002

DrAlexx/pdfium,DrAlexx/pdfium,DrAlexx/pdfium,DrAlexx/pdfium