Phase III Step 1: Make ImageResourceContent manage its own ResourceStatus

third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h

Index: third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h
diff --git a/third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h b/third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h
index 78c55b1e26e90eb7f39e005f11c6bef4c2e6abd7..6351b931253d66bdb82d1dbb5af93471842d7295 100644
--- a/third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h
+++ b/third_party/WebKit/Source/core/loader/resource/ImageResourceContent.h
@@ -93,15 +93,29 @@ class CORE_EXPORT ImageResourceContent final
 
   DECLARE_TRACE();
 
-  // Redirecting methods to Resource.
-  const KURL& Url() const;
-  bool IsAccessAllowed(SecurityOrigin*);
-  const ResourceResponse& GetResponse() const;
+  // Content status and deriving predicates.
+  // https://docs.google.com/document/d/1O-fB83mrE0B_V8gzXNqHgmRLCvstTB4MMi3RnVLr8bE/edit#heading=h.6cyqmir0f30h
+  // Normal transitions:
+  //   kNotStarted -> kPending -> kCached|kLoadError|kDecodeError.
+  // Additional transitions in multipart images:
+  //   kCached -> kLoadError|kDecodeError.
+  // Transitions due to revalidation:
+  //   kCached -> kPending.
+  // Transitions due to reload:
+  //   kCached|kLoadError|kDecodeError -> kPending.
+  //
+  // ImageResourceContent::GetContentStatus() can be different from
+  // ImageResource::GetStatus(). Use ImageResourceContent::GetContentStatus().
+  ResourceStatus GetContentStatus() const;
   bool IsLoaded() const;
   bool IsLoading() const;
   bool ErrorOccurred() const;
   bool LoadFailedOrCanceled() const;
-  ResourceStatus GetStatus() const;
+
+  // Redirecting methods to Resource.
+  const KURL& Url() const;
+  bool IsAccessAllowed(SecurityOrigin*);
+  const ResourceResponse& GetResponse() const;
   const ResourceError& GetResourceError() const;
 
   // For FrameSerializer.
@@ -142,9 +156,11 @@ class CORE_EXPORT ImageResourceContent final
     kShouldDecodeError,
   };
   WARN_UNUSED_RESULT UpdateImageResult UpdateImage(PassRefPtr<SharedBuffer>,
+                                                   ResourceStatus,
                                                    UpdateImageOption,
                                                    bool all_data_received);
 
+  void NotifyStartLoad();
   void DestroyDecodedData();
   void DoResetAnimation();
 
@@ -178,6 +194,7 @@ class CORE_EXPORT ImageResourceContent final
   void NotifyObservers(NotifyFinishOption,
                        const IntRect* change_rect = nullptr);
   void MarkObserverFinished(ImageResourceObserver*);
+  void UpdateToLoadedContentStatus(ResourceStatus);
 
   class ProhibitAddRemoveObserverInScope : public AutoReset<bool> {
    public:
@@ -186,6 +203,7 @@ class CORE_EXPORT ImageResourceContent final
   };
 
   Member<ImageResourceInfo> info_;
+  ResourceStatus content_status_ = ResourceStatus::kNotStarted;
 
   RefPtr<blink::Image> image_;