Alter SkCanvas::drawPicture (devirtualize, take const SkPicture, take pointer)

R=reed@google.com, bsalomon@google.com, mtklein@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/313613004
diff --git a/samplecode/SampleTiling.cpp b/samplecode/SampleTiling.cpp
index a59a802..6bb9c74 100644
--- a/samplecode/SampleTiling.cpp
+++ b/samplecode/SampleTiling.cpp
@@ -158,7 +158,7 @@
         }
 
         SkASSERT(NULL != fTextPicture);
-        canvas->drawPicture(*fTextPicture);
+        canvas->drawPicture(fTextPicture);
     }
 
 private: