FIX: memcpy_76(): add support for non-ARM architectures

Before, memcpy_76() assumed ARM instruction set.  Add preprocessor
guards to use generic memcpy() if not on ARM.

Original patch had args to memcpy_76 backwards.

Change-Id: Ib5375e9de28ab6c2b348731dcdf282d6f7a529c1
memcpy_76(): fix behavior on non-ARM architectures

The destination is passed as the first argument to memcpy_76() and the
source is passed as the second argument.  As originally written in
commit cb5701e, the first argument was called 'src' (despite being the
destination) and the second was called 'dst' (despite being the
source).  The behavior of the memcpy_76() function was correct despite
the backward variable naming.

Commit ad673c1 reversed the naming of the two arguments to clarify the
semantics of the function but failed to reverse the naming in the ARM
assembly code.  This broke the function's behavior on ARM devices.

Commits a8ce1a0 and f4be52e reversed the argument names again.  This
fixed ARM support, but broke non-ARM architectures (the arguments to
memcpy() in the body of the memcpy_76() function were not also
reversed).

This change swaps the argument names again and swaps the names in the
ARM assembly, restoring correct behavior on non-ARM architectures and
aligning the variable names with the function's semantics.

Change-Id: Iaeb2b84b6696e3eebf29617dfdc41c55e5226776
skia: SkPaint::SkPaint(): don't cast away const

This will help avoid bugs like the one fixed in change-id:
Iaeb2b84b6696e3eebf29617dfdc41c55e5226776.

Change-Id: I892423e18f9927f827393d0ff0c923259e07389c
Skia: Introduce caching of unscaled Bitmaps.

This allows skia to choose whether to use the prescaled bitmap or the
unscaled bitmap depending on which would be optimal in the current
situation. This commit also introduces two functions necessary for
properly resizing Rects when using the non-pre-scaled bitmaps.

CRs-fixed: 451681

Change-Id: I36779d8a680a3ced7c28da492e879de02c7e87a5