Avoid purify noise by initializing all member variables

layout/html/base/src/nsIHTMLReflow.h

@@ -311,6 +311,8 @@ protected:
     computedWidth = computedHeight = 0;
     frameType = DetermineFrameType(frame);
     InitConstraints(aPresContext);
+    mAlignCharOffset = 0;
+    mUseAlignCharOffset = 0;
   }
 
   void InitConstraints(nsIPresContext& aPresContext);