Skia: bug fix for SkBitmapProcState_shaderproc.h
Skia: bug fix for SkBitmapProcState_shaderproc.h

Take care of "dx" being 0 case

Change-Id: Ie492c0454d6c8876ea9bb48e911de77cc78a8e98

marlontoe/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,StelixROM/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,StelixROM/android_external_skia