Fix off by one in creating a RasterShape

Source/core/rendering/shapes/RasterShape.cpp

Index: Source/core/rendering/shapes/RasterShape.cpp
diff --git a/Source/core/rendering/shapes/RasterShape.cpp b/Source/core/rendering/shapes/RasterShape.cpp
index be9d2eab07574a31f4f6a269e83aa0db91f34b40..ebb5bd5c8486601dc7ecf07ad11034e502a7150b 100644
--- a/Source/core/rendering/shapes/RasterShape.cpp
+++ b/Source/core/rendering/shapes/RasterShape.cpp
@@ -86,7 +86,7 @@ PassOwnPtr<RasterShapeIntervals> RasterShapeIntervals::computeShapeMarginInterva
 
         marginIntervalGenerator.set(y, intervalAtY);
         int marginY0 = std::max(minY(), y - shapeMargin);
-        int marginY1 = std::min(maxY(), y + shapeMargin);
+        int marginY1 = std::min(maxY() - 1, y + shapeMargin);

[pdr., 2014/06/03 23:08:54]

This is tricky code and I'm certainly not an expert here, but I'd recommend a
small tweak. In general, for (... < ... ++) is by-far the most common
incrementing for loop in Blink, and for(... >= ... --) is the most common
decrementing for loop.

I think this may be easier to understand if we change it to:
int marginY1 = std::min(maxY(), y + shapeMargin + 1);

And update the for loop below to:
for (int marginY = y + 1; marginY < marginY1; ++marginY) {

Possibly updating the variable name to be easier to understand as well. LGTM for
the fix with or without these suggestions.

 
         for (int marginY = y - 1; marginY >= marginY0; --marginY) {
             if (marginY > bounds().y() && intervalAt(marginY).contains(intervalAtY))