printPage to return void instead of bool

public/web/WebPlugin.h

Index: public/web/WebPlugin.h
diff --git a/public/web/WebPlugin.h b/public/web/WebPlugin.h
index 7b6ebaf4fb6d53deb0d157f1aadf4198ffe52d60..e5a6258224646c4c16fc3d48c3432d0a086548ae 100644
--- a/public/web/WebPlugin.h
+++ b/public/web/WebPlugin.h
@@ -133,6 +133,9 @@ public:
 
     // Prints the page specified by pageNumber (0-based index) into the supplied canvas.
     virtual bool printPage(int pageNumber, WebCanvas* canvas) { return false; }
+    // TODO: Remove third parameter when both blink and chromium changes land for bug496765
+    virtual void printPage(int pageNumber, WebCanvas* canvas, bool unused) { }
+
     // Ends the print operation.
     virtual void printEnd() { }