Make sure line widths in the range of 0px and 1px are rounded up to 1px for visibility.

third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h

Index: third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h b/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h
index e404ef65c614cd2cb476a38b9f45699938cc5675..0f7707acfb889cdd7bd2c5a175950a2aaff5ff34 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h
+++ b/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h
@@ -137,13 +137,15 @@ T StyleBuilderConverter::convertLineWidth(StyleResolverState& state, const CSSVa
     if (valueID == CSSValueInvalid) {
         // Any original result that was >= 1 should not be allowed to fall below 1.
         // This keeps border lines from vanishing.
-        T result = primitiveValue.computeLength<T>(state.cssToLengthConversionData());
+        double result = primitiveValue.computeLength<double>(state.cssToLengthConversionData());
         if (state.style()->effectiveZoom() < 1.0f && result < 1.0) {

[alancutter (OOO until 2018), 2015/10/27 04:10:32]

Is this code path redundant now?

[nainar, 2015/10/27 05:30:18]

Done.

             T originalLength = primitiveValue.computeLength<T>(state.cssToLengthConversionData().copyWithAdjustedZoom(1.0));
             if (originalLength >= 1.0)
                 return 1.0;
         }
-        return result;
+        if (result > 0.0 && result < 1.0)
+            return 1.0;
+        return primitiveValue.computeLength<T>(state.cssToLengthConversionData());

[alancutter (OOO until 2018), 2015/10/27 04:10:32]

Can we just call clampTo<T>() instead of calling computeLength() twice?

[nainar, 2015/10/27 05:30:18]

Done.

     }
     ASSERT_NOT_REACHED();
     return 0;