Caching the result of readPixelsSupported The call was calling GR_GL_GetIntegerv 2 times for each readPixels and thus was causing a loss of performance (resubmit of issue 344793008) Benchmark url: http://packages.gkny.fr/tst/index.html BUG=skia:2681 Committed: https://skia.googlesource.com/skia/+/753a2964afe5661ce9b2a8ca77ca9d0aabd3173c Committed: https://skia.googlesource.com/skia/+/8339371f1ec3c57a0741932fd96bff32c53d4e54 Review URL: https://codereview.chromium.org/364193004