Move SkImage::encode to SkImage_Codec.cpp.

Chrome depends on SkImage.cpp, but does not include SkImageDecoder,
so having SkImage::encode in SkImage.cpp breaks chromium. Temporarily
fix the problem by moving the implementation into SkImage_Codec.cpp.

The larger fix will be to solve
https://code.google.com/p/skia/issues/detail?id=1275

R=reed@google.com, robertphillips@google.com

Author: scroggo@google.com

Review URL: https://chromiumcodereview.appspot.com/15314004

git-svn-id: http://skia.googlecode.com/svn/trunk@9204 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed