cc: Start using raster/eviction iterators in tile manager

cc/layers/picture_layer_impl.h

Index: cc/layers/picture_layer_impl.h
diff --git a/cc/layers/picture_layer_impl.h b/cc/layers/picture_layer_impl.h
index 80d09dde721ad2e533c11d819f4241e986c6327c..9d552197ad904b93f90d8baeb4d7b85142b607f9 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -39,6 +39,8 @@ class CC_EXPORT PictureLayerImpl
     LayerRasterTileIterator& operator++();
     operator bool() const;
 
+    bool HasTilesRequiredForActivation() const;

[reveman, 2014/05/20 23:01:00]

Everything related to HasTilesRequiredForActivation is unnecessary once
https://codereview.chromium.org/287643004/ lands, right?

[vmpstr, 2014/05/27 22:41:32]

That's correct. I'm keeping it here just for testing, but it all goes away with
the activation patch. One concern with rebasing is that I'll probably just end
up calling the check after every rasterizer notification, since I have no other
hints to determine whether it's a good time to activate.

[reveman, 2014/05/28 16:04:12]

See my comment on latest patch.

+
    private:
     enum IteratorType { LOW_RES, HIGH_RES, NUM_ITERATORS };