Revert of Slim Skia down to just one murmur3 implementation.

Revert of Slim Skia down to just one murmur3 implementation. (https://codereview.chromium.org/376183004/)

Reason for revert:
broke 10.6 compile

[17:13:56.863876] [4/336] CXX obj/src/core/core.SkBBoxHierarchyRecord.o
[17:13:56.863997] FAILED: c++ -MMD -MF obj/src/core/core.SkBBoxRecord.o.d -DSK_INTERNAL -DSK_GAMMA_SRGB -DSK_GAMMA_APPLY_TO_A8 -DSK_SCALAR_TO_FLOAT_EXCLUDED -DSK_ALLOW_STATIC_GLOBAL_INITIALIZERS=1 -DSK_SUPPORT_GPU=1 -DSK_SUPPORT_OPENCL=0 -DSK_FORCE_DISTANCEFIELD_FONTS=0 -DSK_SCALAR_IS_FLOAT -DSK_BUILD_FOR_MAC -DSK_USE_POSIX_THREADS -DSK_RELEASE -DNDEBUG -I../../include/config -I../../include/core -I../../include/pathops -I../../include/pipe -I../../include/ports -I../../include/utils -I../../include/xml -I../../src/core -I../../src/sfnt -I../../src/image -I../../src/opts -I../../src/utils -I../../include/utils/mac -I../../include/gpu -I../../src/gpu -fasm-blocks -mpascal-strings -O3 -gdwarf-2 -Wnewline-eof -mmacosx-version-min=10.6 -arch x86_64 -mssse3 -fvisibility=hidden -fvisibility-inlines-hidden  -c ../../src/core/SkBBoxRecord.cpp -o obj/src/core/core.SkBBoxRecord.o
[17:13:56.864085] In file included from ../../src/core/SkPictureFlat.h:14,
[17:13:56.864130]                  from ../../src/core/SkPictureData.h:14,
[17:13:56.864173]                  from ../../src/core/SkPictureRecord.h:18,
[17:13:56.864217]                  from ../../src/core/SkBBoxRecord.h:12,
[17:13:56.864261]                  from ../../src/core/SkBBoxRecord.cpp:9:
[17:13:56.864336] ../../src/core/SkChecksum.h: In static member function ‘static uint32_t SkChecksum::Compute(const uint32_t*, size_t)’:
[17:13:56.864397] ../../src/core/SkChecksum.h:127: error: invalid conversion from ‘const uint32_t*’ to ‘const uint32_t*’
[17:13:56.864462] ../../src/core/SkChecksum.h:128: error: invalid conversion from ‘const uint32_t*’ to ‘const uint32_t*’
[17:13:56.864510] ../../src/core/SkChecksum.h:129: error: comparison between distinct pointer types ‘const uint32_t*’ and ‘const uint32_t*’ lacks a cast


Original issue's description:
> Slim Skia down to just one murmur3 implementation.
> 
> BUG=skia:
> 
> Committed: https://skia.googlesource.com/skia/+/6ac0037b70410ff7d5ce5788bc89314223e1a587
> 
> Committed: https://skia.googlesource.com/skia/+/67a3271f0de9ccc32d559b042b862528272047cc
> 
> Committed: https://skia.googlesource.com/skia/+/53d435990bdb4d14df78013da45a9364d0287ebe

TBR=mtklein@google.com,mtklein@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Committed: https://skia.googlesource.com/skia/+/bbf9f6d1cbb94d3486072228781f6e3b6e2252e4

[reed1, 2014-07-10 21:29:10]

Created Revert of Slim Skia down to just one murmur3 implementation.

[commit-bot: I haz the power, 2014-07-10 21:29:40]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/reed@google.com/381253003/1

[commit-bot: I haz the power, 2014-07-10 21:29:46]

Change committed as bbf9f6d1cbb94d3486072228781f6e3b6e2252e4