Removing the dependency on GraphicsContext for drawing images in 2D canvas

Source/platform/graphics/skia/SkiaUtils.h

 /*
  * Copyright (c) 2006,2007,2008, 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:
  *
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  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 109 matching lines @@
 InterpolationQuality limitInterpolationQuality(const GraphicsContext*, InterpolationQuality resampling);
 
 InterpolationQuality computeInterpolationQuality(
     const SkMatrix&,
     float srcWidth,
     float srcHeight,
     float destWidth,
     float destHeight,
     bool isDataComplete = true);
 
-bool shouldDrawAntiAliased(const GraphicsContext*, const SkRect& destRect);
-
 // This replicates the old skia behavior when it used to take radius for blur. Now it takes sigma.
 inline SkScalar skBlurRadiusToSigma(SkScalar radius)
 {
     SkASSERT(radius >= 0);
     return 0.288675f * radius + 0.5f;
 }
 
+template<typename DrawFunc>
+void drawPlatformFocusRing(const DrawFunc& drawFunc, SkColor color, int width)

[Stephen White, 2015/05/29 17:26:37]

It looks like the two call sites which draw focus rings as paths provide almost
identical lambdas.

Rather than exposing the functor as an API here, could we provide two functions
here in SkiaUtils (drawPlatformFocusRingPath and drawPlatformFocusRingRect)
which use a lambda internally if necessary?

+{
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setColor(color);
+
+#if OS(MACOSX)
+    paint.setStrokeWidth(width);
+    paint.setAlpha(64);
+    float cornerRadius = (width - 1) * 0.5f;
+#else
+    paint.setStrokeWidth(1);
+    const float cornerRadius = 1;
+#endif
+
+    drawFunc(paint, cornerRadius);
+
+#if OS(MACOSX)
+    // Inner part
+    paint.setAlpha(128);
+    paint.setStrokeWidth(paint.getStrokeWidth() * 0.5f);
+    drawFunc(paint, cornerRadius);
+#endif
+}
+
 } // namespace blink
 
 #endif  // SkiaUtils_h