cc: Clean up RecordingSource API

cc/playback/recording_source.h

Index: cc/playback/recording_source.h
diff --git a/cc/playback/recording_source.h b/cc/playback/recording_source.h
index 36d0511d358ab2662128f4768900e722e9170d83..8f443425f135cc2af08b6d32f46cb8547120bd1d 100644
--- a/cc/playback/recording_source.h
+++ b/cc/playback/recording_source.h
@@ -70,14 +70,13 @@ class CC_EXPORT RecordingSource {
       bool can_use_lcd_text) const;
   virtual bool IsSuitableForGpuRasterization() const;
 
-  gfx::Rect recorded_viewport() const { return recorded_viewport_; }
+  gfx::Rect recorded_viewport() const { return inputs_.recorded_viewport; }
 
   const DisplayItemList* GetDisplayItemList();
 
  protected:
   void Clear();
 
-  gfx::Rect recorded_viewport_;
   gfx::Size size_;
   int slow_down_raster_scale_factor_for_debug_;
   bool generate_discardable_images_metadata_;
@@ -87,8 +86,17 @@ class CC_EXPORT RecordingSource {
   SkColor solid_color_;
   SkColor background_color_;
 
-  scoped_refptr<DisplayItemList> display_list_;
-  size_t painter_reported_memory_usage_;
+  // Encapsulates all data received from the ContentLayerClient.
+  struct Inputs {
+    Inputs();
+    ~Inputs();
+
+    gfx::Rect recorded_viewport;
+    scoped_refptr<DisplayItemList> display_list;
+    size_t painter_reported_memory_usage = 0;
+  };
+
+  Inputs inputs_;
 
  private:
   void UpdateInvalidationForNewViewport(const gfx::Rect& old_recorded_viewport,