Bug 1002354 - Proxy nsIScreenManager and nsIScreen's from the child process to the parent process, with caching. r=roc,jimm,smichaud,snorp.

Changes to nsIScreen and nsIScreenManager were reviewed by roc.
Changes to dom/ipc were reviewed by jimm.
Changes to gfx/src/nsDeviceContext.cpp were reviewed by roc.
Changes to widget/android were reviewed by snorp.
Changes to widget/cocoa were reviewed by smichaud.
Changes to widget/gtk were reviewed by roc.
Changes to widget/windows were reviewed by jimm.
Changes to widget/xpwidgets were reviewed by roc.

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extra : rebase_source : 3ebb5763d75d16f73b3cb5e4fc5621188b6c9622