update bitmapshader to avoid potential rendering error for kA8_Config

update bitmapshader to avoid potential rendering error for kA8_Config

A local matrix is set to the shader, which will show the potential error for SkCanvas::drawBitmap when the bitmap is kA8_Config, as well as the potential error for drawing a geometry with a bitmapshader who's bitmap is kA8_Config.

A simple case is also added for SkCanvas::drawBitmap when the bitmap is kA8_Config, but there is not shader. Then the drawing area will be colorized by the solid color set in SkPaint.

BUG=skia:2278
BUG=skia:2293
R=reed@google.com, bsalomon@google.com

Author: yunchao.he@intel.com

Review URL: https://codereview.chromium.org/204143004

git-svn-id: http://skia.googlecode.com/svn/trunk@13904 2bbb7eff-a529-9590-31e7-b0007b416f81