cc: Remove all blimp code from cc.

cc/playback/display_item.h

Index: cc/playback/display_item.h
diff --git a/cc/playback/display_item.h b/cc/playback/display_item.h
index 4e74e9079e76e9f9da7c3400aba25af25a49ff99..a57096213813ba41c49492962451411e6175451f 100644
--- a/cc/playback/display_item.h
+++ b/cc/playback/display_item.h
@@ -18,10 +18,6 @@ class SkCanvas;
 
 namespace cc {
 
-namespace proto {
-class DisplayItem;
-}  // namespace proto
-
 class CC_EXPORT DisplayItem {
  public:
   enum Type {
@@ -42,7 +38,6 @@ class CC_EXPORT DisplayItem {
 
   virtual ~DisplayItem() {}
 
-  virtual void ToProtobuf(proto::DisplayItem* proto) const = 0;
   virtual sk_sp<const SkPicture> GetPicture() const;
   virtual void Raster(SkCanvas* canvas,
                       SkPicture::AbortCallback* callback) const = 0;