Avoid uninitialized memory when decomposing a matrix fails.

Source/platform/transforms/TransformationMatrix.h

Index: Source/platform/transforms/TransformationMatrix.h
diff --git a/Source/platform/transforms/TransformationMatrix.h b/Source/platform/transforms/TransformationMatrix.h
index ba3b92482f362db25eb69b56a4f0116d86bd8e0c..3a9a0bd387c493a8448c822666747f585349ffcb 100644
--- a/Source/platform/transforms/TransformationMatrix.h
+++ b/Source/platform/transforms/TransformationMatrix.h
@@ -254,8 +254,8 @@ public:
         double perspectiveX, perspectiveY, perspectiveZ, perspectiveW;
     } DecomposedType;
 
-    bool decompose(DecomposedType& decomp) const;
-    void recompose(const DecomposedType& decomp);
+    bool decompose(DecomposedType&) const WARN_UNUSED_RETURN;
+    void recompose(const DecomposedType&);
 
     void blend(const TransformationMatrix& from, double progress);