Eliminate copies of encoded image data

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 581 matching lines @@
       'graphics/ProfilingCanvas.cpp',
       'graphics/ProfilingCanvas.h',
       'graphics/RecordingImageBufferSurface.cpp',
       'graphics/RecordingImageBufferSurface.h',
       'graphics/ReplayingCanvas.cpp',
       'graphics/ReplayingCanvas.h',
       'graphics/StaticBitmapImage.cpp',
       'graphics/StaticBitmapImage.h',
       'graphics/StrokeData.cpp',
       'graphics/StrokeData.h',
-      'graphics/ThreadSafeDataTransport.cpp',
-      'graphics/ThreadSafeDataTransport.h',
       'graphics/UnacceleratedImageBufferSurface.cpp',
       'graphics/UnacceleratedImageBufferSurface.h',
       'graphics/compositing/PaintArtifactCompositor.cpp',
       'graphics/compositing/PaintArtifactCompositor.h',
       'graphics/cpu/arm/WebGLImageConversionNEON.h',
       'graphics/cpu/x86/WebGLImageConversionSSE.h',
       'graphics/filters/DistantLightSource.cpp',
       'graphics/filters/DistantLightSource.h',
       'graphics/filters/FEBlend.cpp',
       'graphics/filters/FEBlend.h',
@@ skipping 119 matching lines @@
       'graphics/skia/SkSizeHash.h',
       'graphics/skia/SkiaUtils.cpp',
       'graphics/skia/SkiaUtils.h',
       'image-decoders/FastSharedBufferReader.cpp',
       'image-decoders/FastSharedBufferReader.h',
       'image-decoders/ImageAnimation.h',
       'image-decoders/ImageDecoder.cpp',
       'image-decoders/ImageDecoder.h',
       'image-decoders/ImageFrame.cpp',
       'image-decoders/ImageFrame.h',
+      'image-decoders/ROBufferSegmentReader.cpp',
+      'image-decoders/ROBufferSegmentReader.h',

[Peter Kasting, 2016/03/23 02:42:57]

Nit: I think it would be nicer to spell out "ReadOnly" in the file name instead
of saving a few characters with "RO".

[scroggo_chromium, 2016/03/24 13:59:44]

This reads from an object called "SkROBuffer", so I think this name makes more
sense, unless we change the name of the Skia class.

[Peter Kasting, 2016/03/24 22:05:43]

It's a judgment call.  I would try to apply the same logic here as for
DataSegmentReader -- do we want to closely match the underlying Skia type name
(in which case SkDataSegmentReader might be better) or are we trying to write a
name that's readable without reference to the SKia typename, or somewhere in the
middle?

I would probably prefer SkROBufferSegmentReader and ReadOnlyBufferSegmentReader
to ROBufferSegmentReader, but all have their downsides, so as long as you're
consistent in the end go with what you think is best.

[scroggo_chromium, 2016/03/25 01:05:10]

I've stuck with DataSegmentReader and ROBufferSegmentReader, which both mirror
their Skia types minus the Sk. I also moved them into factories, so if we don't
like the names we can change them in few places.

+      'image-decoders/SharedBufferSegmentReader.cpp',
+      'image-decoders/SharedBufferSegmentReader.h',
+      'image-decoders/SegmentReader.h',
+      'image-decoders/SkDataSegmentReader.h',
+      'image-decoders/SkDataSegmentReader.cpp',
       'image-decoders/bmp/BMPImageDecoder.cpp',
       'image-decoders/bmp/BMPImageDecoder.h',
       'image-decoders/bmp/BMPImageReader.cpp',
       'image-decoders/bmp/BMPImageReader.h',
       'image-decoders/gif/GIFImageDecoder.cpp',
       'image-decoders/gif/GIFImageDecoder.h',
       'image-decoders/gif/GIFImageReader.cpp',
       'image-decoders/gif/GIFImageReader.h',
       'image-decoders/ico/ICOImageDecoder.cpp',
       'image-decoders/ico/ICOImageDecoder.h',
@@ skipping 265 matching lines @@
       'geometry/FloatPointTest.cpp',
       'geometry/FloatPolygonTest.cpp',
       'geometry/FloatRoundedRectTest.cpp',
       'geometry/FloatSizeTest.cpp',
       'geometry/GeometryTestHelpers.cpp',
       'geometry/LayoutRectOutsetsTest.cpp',
       'geometry/RegionTest.cpp',
       'graphics/ContiguousContainerTest.cpp',
       'graphics/GraphicsContextTest.cpp',
       'graphics/RecordingImageBufferSurfaceTest.cpp',
-      'graphics/ThreadSafeDataTransportTest.cpp',
       'graphics/filters/FilterOperationsTest.cpp',
       'graphics/filters/ImageFilterBuilderTest.cpp',
       'graphics/gpu/DrawingBufferTest.cpp',
       'graphics/paint/DisplayItemClientTest.cpp',
       'graphics/paint/DisplayItemTest.cpp',
       'graphics/paint/PaintArtifactToSkCanvasTest.cpp',
       'graphics/paint/PaintChunkerTest.cpp',
       'graphics/paint/PaintControllerTest.cpp',
       'image-decoders/FastSharedBufferReaderTest.cpp',
       'image-decoders/ImageDecoderTest.cpp',
@@ skipping 87 matching lines @@
       ['OS!="mac"',
         {
           'platform_test_files': [
             'scroll/ScrollAnimatorTest.cpp',
           ],
         }
       ],
     ],
   },
 }