cc: Remove save/restore from DrawingDisplayItem::Raster.

cc/resources/drawing_display_item.cc

Index: cc/resources/drawing_display_item.cc
diff --git a/cc/resources/drawing_display_item.cc b/cc/resources/drawing_display_item.cc
index 91ab3fb0d38103b37a08a0ab9e8a9c25df79ee49..578da5cd2dec64f6d0fe6f49abfc8d39672c8644 100644
--- a/cc/resources/drawing_display_item.cc
+++ b/cc/resources/drawing_display_item.cc
@@ -26,12 +26,12 @@ DrawingDisplayItem::~DrawingDisplayItem() {
 
 void DrawingDisplayItem::Raster(SkCanvas* canvas,
                                 SkDrawPictureCallback* callback) const {
-  canvas->save();
+  // SkPicture always does a wrapping save/restore on the canvas, so it is not
+  // necessary here.
   if (callback)
     picture_->playback(canvas, callback);
   else
     canvas->drawPicture(picture_.get());
-  canvas->restore();
 }
 
 bool DrawingDisplayItem::IsSuitableForGpuRasterization() const {