Bug 994190 - 'Modify main-thread IndexedDB to use PBackground', r=khuey.

--HG--
rename : dom/indexedDB/ipc/SerializationHelpers.h => dom/indexedDB/SerializationHelpers.h
rename : dom/indexedDB/ipc/unit/head.js => dom/indexedDB/test/unit/xpcshell-head-child-process.js
rename : dom/indexedDB/test/unit/head.js => dom/indexedDB/test/unit/xpcshell-head-parent-process.js
rename : dom/ipc/Blob.h => dom/ipc/BlobParent.h
rename : dom/ipc/FileDescriptorSetChild.cpp => ipc/glue/FileDescriptorSetChild.cpp
rename : dom/ipc/FileDescriptorSetChild.h => ipc/glue/FileDescriptorSetChild.h
rename : dom/ipc/FileDescriptorSetParent.cpp => ipc/glue/FileDescriptorSetParent.cpp
rename : dom/ipc/FileDescriptorSetParent.h => ipc/glue/FileDescriptorSetParent.h
rename : dom/ipc/PFileDescriptorSet.ipdl => ipc/glue/PFileDescriptorSet.ipdl