This change adds an enum value and a description of the expected
implementations to the EGL_ANDROID_recordable extension specification.
It also adds the new enum value to the 'eglext.h' header.
Change-Id: Ia0de2d5613708445ff83b85a7e550f9417531ee4
ANDROID_swap_rectangle allows to specify the rectangle affected by eglSwapBuffers(), anything outside of this rectangle is unchanged. in particular EGL_BUFFER_DESTROYED only applies to that rectangle. This extension as well as EGL_BUFFER_PRESERVED allow major optimizations on surfaceflinger, which can redraw only the dirty area during compositing.
However, ANDROID_swap_rectangle allows further optimizations in EGL by reducing the amount of copy-back needed. ANDROID_swap_rectangle is particularily important for software implementations.
