Reopened: Caching the result of readPixelsSupported

gyp/tests.gypi

 # Common gypi for unit tests.
 {
   'include_dirs': [
     '../src/core',
     '../src/effects',
     '../src/image',
     '../src/lazy',
     '../src/images',
     '../src/pathops',
     '../src/pdf',
@@ skipping 180 matching lines @@
     '../tests/SkBase64Test.cpp',
     '../tests/SkResourceCacheTest.cpp',
     '../tests/SmallAllocatorTest.cpp',
     '../tests/SortTest.cpp',
     '../tests/SrcOverTest.cpp',
     '../tests/StreamTest.cpp',
     '../tests/StringTest.cpp',
     '../tests/StrokeTest.cpp',
     '../tests/SurfaceTest.cpp',
     '../tests/TArrayTest.cpp',
+    '../tests/THashCache.cpp',
     '../tests/TLSTest.cpp',
     '../tests/TSetTest.cpp',
     '../tests/TextBlobTest.cpp',
     '../tests/TextureCompressionTest.cpp',
     '../tests/TileGridTest.cpp',
     '../tests/ToUnicodeTest.cpp',
     '../tests/TracingTest.cpp',
     '../tests/TypefaceTest.cpp',
     '../tests/UnicodeTest.cpp',
     '../tests/UtilsTest.cpp',
@@ skipping 10 matching lines @@
     '../src/utils/debugger/SkObjectParser.h',
     '../src/utils/debugger/SkObjectParser.cpp',
 
     '../tests/PipeTest.cpp',
     '../src/pipe/utils/SamplePipeControllers.cpp',
 
     '../tests/TDStackNesterTest.cpp',
     '../experimental/PdfViewer/src/SkTDStackNester.h',
   ],
 }