Add UMA to estimate deroppable memory usage of encoded data size in Resources

third_party/WebKit/Source/core/fetch/ImageResource.h

Index: third_party/WebKit/Source/core/fetch/ImageResource.h
diff --git a/third_party/WebKit/Source/core/fetch/ImageResource.h b/third_party/WebKit/Source/core/fetch/ImageResource.h
index da11324a76b75831bae1dbdf4ee8ecf76740af09..f348355f6aca703f4360206728309110e6a5f7af 100644
--- a/third_party/WebKit/Source/core/fetch/ImageResource.h
+++ b/third_party/WebKit/Source/core/fetch/ImageResource.h
@@ -217,6 +217,8 @@ class CORE_EXPORT ImageResource final
   // Indicates if this ImageResource is either attempting to load a placeholder
   // image, or is a (possibly broken) placeholder image.
   bool m_isPlaceholder;
+
+  bool m_isRefetchableFromDiskCache;

[yhirano, 2016/11/16 11:25:38]

How about having a function that turns this flag off and calling the function
from the StylefetchedImage constructor?

[yhirano, 2016/11/16 11:25:38]

I think including "data" or "body" in the name is a good idea.
m_isAllowedToRefetchData[FromDiskCache], for example?

Anyway, please write some comments.

[hajimehoshi, 2016/11/16 12:15:48]

Done. (setNotRefetchableDataFromDiskCache seems weird. Do you have any
suggestion?)

[hajimehoshi, 2016/11/16 12:19:48]

I mean the name setNotRefetchableDataFromDiskCache is weird but I couldn't come
up with a better name...

[yhirano, 2016/11/17 02:16:56]

Is it better to focus on dropping / discarding the encoded data rather than
refeching in the field name? After all that is what you want to do. But it's up
to you.

 };
 
 DEFINE_RESOURCE_TYPE_CASTS(Image);