Creating PNG images from web content to be used by OverviewMode navigation

athena/activity/public/activity_view_model.h

Index: athena/activity/public/activity_view_model.h
diff --git a/athena/activity/public/activity_view_model.h b/athena/activity/public/activity_view_model.h
index 7412af224946908dd9839dbb6584bb9f8cf4d1c9..44537bdc602328ef3d5733fa5262eb4f58e5dda2 100644
--- a/athena/activity/public/activity_view_model.h
+++ b/athena/activity/public/activity_view_model.h
@@ -6,14 +6,12 @@
 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 
 #include "athena/athena_export.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
+#include "ui/gfx/image/image.h"

[oshima, 2014/09/22 16:10:27]

forward decl should be enough

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

Done.

 
 typedef unsigned int SkColor;
 
-namespace gfx {
-class ImageSkia;
-}
-
 namespace views {
 class View;
 class Widget;
@@ -58,8 +56,9 @@ class ATHENA_EXPORT ActivityViewModel {
   // overview mode. The returned image can have no size if either a view exists
   // or the activity has not yet been loaded. In that case
   // GetRepresentativeColor() should be used to clear the preview area.
+  // The ownership gets passed to the caller.
   // Note: We intentionally do not use a layer / view for this.
-  virtual gfx::ImageSkia GetOverviewModeImage() = 0;
+  virtual scoped_ptr<gfx::Image> GetOverviewModeImage() = 0;

[oshima, 2014/09/22 16:10:28]

Is there particular reason why this needs to be scoped_ptr?
The image data in gfx::Image is ref counted.

[sadrul, 2014/09/22 16:13:32]

Why this change?

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

Hmm. I was under the misconception that Image was not auto managed, only
SkiaImage. Done.

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

I have found the PNG decoding to be done with gfx::Image. According to
Image::ToImageSkia(): "The returned result is a weak pointer owned by and scoped
to the life of the Image.". So to keep ImageSkia we would have needed to add
some kind of release call. However it appeared to be much simpler if the caller
can use Image::ToImageSkia and release the bits on its own when done.

Makes sense - or do you see a better solution?

[oshima, 2014/09/24 00:40:00]

gfx::Image stores images in ImageStorage, which is refcounted and shared between
gfx::Image instances originated from the same instance.

I agree that the comment is a bit misleading. It simply means the returned point
is valid so long
as the gfx::Image(s) owning the image are live.

 
   // Prepares the contents view for overview.
   virtual void PrepareContentsForOverview() = 0;