Draw thin slices of an image w/ anti-aliasing for 2D <canvas>

Source/platform/graphics/GraphicsContext.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 118 matching lines @@
 
     SkDrawLooper* drawLooper() const { return immutableState()->drawLooper(); }
 
     FloatRect getClipBounds() const;
     bool getTransformedClipBounds(FloatRect* bounds) const;
     SkMatrix getTotalMatrix() const;
 
     void setShouldAntialias(bool antialias) { mutableState()->setShouldAntialias(antialias); }
     bool shouldAntialias() const { return immutableState()->shouldAntialias(); }
 
+    // Disable the anti-aliasing optimization for scales/multiple-of-90-degrees
+    // rotations of thin ("hairline") images.
+    // Note: This will only be reliable when the device pixel scale/ratio is
+    // fixed (e.g. when drawing to context backed by an ImageBuffer).
+    void disableAntialiasingOptimizationForHairlineImages() { ASSERT(!isRecording()); m_antialiasHairlineImages = true; }
+    bool shouldAntialiasHairlineImages() const { return m_antialiasHairlineImages; }
+
     void setShouldClampToSourceRect(bool clampToSourceRect) { mutableState()->setShouldClampToSourceRect(clampToSourceRect); }
     bool shouldClampToSourceRect() const { return immutableState()->shouldClampToSourceRect(); }
 
     void setShouldSmoothFonts(bool smoothFonts) { mutableState()->setShouldSmoothFonts(smoothFonts); }
     bool shouldSmoothFonts() const { return immutableState()->shouldSmoothFonts(); }
 
     // Turn off LCD text for the paint if not supported on this context.
     void adjustTextRenderMode(SkPaint*);
     bool couldUseLCDRenderedText();
 
@@ skipping 348 matching lines @@
     bool m_trackTextRegion : 1;
     SkRect m_textRegion;
 
     // Are we on a high DPI display? If so, spelling and grammar markers are larger.
     bool m_useHighResMarker : 1;
     // FIXME: Make this go away: crbug.com/236892
     bool m_updatingControlTints : 1;
     bool m_accelerated : 1;
     bool m_isCertainlyOpaque : 1;
     bool m_printing : 1;
+    bool m_antialiasHairlineImages : 1;
 };
 
 } // namespace WebCore
 
 #endif // GraphicsContext_h