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/SamplePictFile.cpp b/samplecode/SamplePictFile.cpp
index 7b9584d..9e9764c 100644
--- a/samplecode/SamplePictFile.cpp
+++ b/samplecode/SamplePictFile.cpp
@@ -100,7 +100,7 @@
             *picture = LoadPicture(fFilename.c_str(), fBBox);
         }
         if (*picture) {
-            canvas->drawPicture(**picture);
+            canvas->drawPicture(*picture);
         }
     }
 
@@ -140,7 +140,7 @@
 
             if (false) {
                 SkSurface* surf = SkSurface::NewRasterPMColor(pic->width(), pic->height());
-                surf->getCanvas()->drawPicture(*pic);
+                surf->getCanvas()->drawPicture(pic);
                 surf->unref();
             }
             if (false) { // re-record