Revert of Remove unused (by clients) SkUnitMapper (https://codereview.chromium.org/283273002/) (https://codereview.chromium.org/288343009/)

Reason for revert:
required blink change failed to land

Original issue's description:
> Remove unused (by clients) SkUnitMapper (https://codereview.chromium.org/283273002/)
>
> This reverts commit dd50c83b5b34dab3a077741861b50ed1f2bc6b8f.
>
> BUG=skia:
>
> Committed: http://code.google.com/p/skia/source/detail?r=14830

R=scroggo@google.com, reed@google.com
TBR=reed@google.com, scroggo@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/296823008

git-svn-id: http://skia.googlecode.com/svn/trunk@14838 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/DeferredCanvasTest.cpp b/tests/DeferredCanvasTest.cpp
index 9ffb790..a5a763a 100644
--- a/tests/DeferredCanvasTest.cpp
+++ b/tests/DeferredCanvasTest.cpp
@@ -359,7 +359,7 @@
         const SkColor colors[2] = {SK_ColorWHITE, SK_ColorWHITE};
         const SkScalar pos[2] = {0, SK_Scalar1};
         SkShader* shader = SkGradientShader::CreateTwoPointConical(
-            pt1, r1, pt2, r2, colors, pos, 2, SkShader::kClamp_TileMode);
+            pt1, r1, pt2, r2, colors, pos, 2, SkShader::kClamp_TileMode, NULL);
         paint.setShader(shader)->unref();
         canvas->drawRect(fullRect, paint);
         REPORTER_ASSERT(reporter, !canvas->isFreshFrame());