Revert of Remove gpu support for willUseHWAALines.

src/gpu/GrDrawTarget.h

Index: src/gpu/GrDrawTarget.h
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index 0c03e34041c1d2f654e4b6a2b37c9e35fbb48b8a..c868e56aa79a733553875a84e5475cc0309acca0 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -111,6 +111,12 @@
         // return false;
         return !this->canApplyCoverage();
     }
+
+    /**
+     * Given the current draw state and hw support, will HW AA lines be used (if
+     * a line primitive type is drawn)?
+     */
+    bool willUseHWAALines() const;
 
     /**
      * There are three types of "sources" of geometry (vertices and indices) for