PDF: Add (low-memory) SkPDFBitmap class

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 59 matching lines @@
     '../tests/ClipCacheTest.cpp',
     '../tests/ClipCubicTest.cpp',
     '../tests/ClipStackTest.cpp',
     '../tests/ClipperTest.cpp',
     '../tests/ColorFilterTest.cpp',
     '../tests/ColorPrivTest.cpp',
     '../tests/ColorTest.cpp',
     '../tests/DashPathEffectTest.cpp',
     '../tests/DataRefTest.cpp',
     '../tests/DeferredCanvasTest.cpp',
+    '../tests/DeflateWStream.cpp',
     '../tests/DequeTest.cpp',
     '../tests/DeviceLooperTest.cpp',
     '../tests/DiscardableMemoryPoolTest.cpp',
     '../tests/DiscardableMemoryTest.cpp',
     '../tests/DocumentTest.cpp',
     '../tests/DrawBitmapRectTest.cpp',
     '../tests/DrawPathTest.cpp',
     '../tests/DrawTextTest.cpp',
     '../tests/DynamicHashTest.cpp',
     '../tests/EmptyPathTest.cpp',
@@ skipping 137 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',
   ],
 }