SkScalerContextRec::computeMatrices to return status.

src/core/SkScalerContext.h

Index: src/core/SkScalerContext.h
diff --git a/src/core/SkScalerContext.h b/src/core/SkScalerContext.h
index ffde83cb0a9e456f6baf035ca7feb8358983069b..87d022a8eeecfadb8c07f8200f72c633b4fa2d83 100644
--- a/src/core/SkScalerContext.h
+++ b/src/core/SkScalerContext.h
@@ -146,8 +146,9 @@ struct SkScalerContextRec {
      *  @param remainingWithoutRotation apply after scale to apply the total matrix sans rotation.
      *  @param remainingRotation apply after remainingWithoutRotation to apply the total matrix.
      *  @param total the total matrix.
+     *  @return false if the matrix was singular. The output will be valid but not invertable.
      */
-    void computeMatrices(PreMatrixScale preMatrixScale,
+    bool computeMatrices(PreMatrixScale preMatrixScale,
                          SkVector* scale, SkMatrix* remaining,
                          SkMatrix* remainingWithoutRotation = nullptr,
                          SkMatrix* remainingRotation = nullptr,