compositor-worker: cc->blink mutation plumbing

third_party/WebKit/public/web/WebWidget.h

Index: third_party/WebKit/public/web/WebWidget.h
diff --git a/third_party/WebKit/public/web/WebWidget.h b/third_party/WebKit/public/web/WebWidget.h
index ceb006fab242ba7440712515e0060f2649f0d4de..30b4c58915390a27f51008254f37b407e8704408 100644
--- a/third_party/WebKit/public/web/WebWidget.h
+++ b/third_party/WebKit/public/web/WebWidget.h
@@ -1,4 +1,3 @@
-
 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ -52,6 +51,7 @@ class WebInputEvent;
 class WebLayoutAndPaintAsyncCallback;
 class WebPagePopup;
 class WebString;
+struct WebCompositorMutations;
 struct WebPoint;
 template <typename T> class WebVector;
 
@@ -148,6 +148,9 @@ public:
     };
     virtual void recordFrameTimingEvent(FrameTimingEventType eventType, int64_t RectId, const WebVector<WebFrameTimingEvent>& events) { }
 
+    // Called to notify the WebWidget about the mutations made to the elements from a compositor worker.
+    virtual void applyMutations(const WebCompositorMutations&) {}

[jbroman, 2016/01/23 23:55:10]

nit: Would you mind including "compositor" or similar in the method name? It's
not obvious until you look at the parameters that this has to do with
compositing (as opposed to mutating some other aspect of a widget).

I'm not a public/ owner, but since this CL already requires that
cc::LayerTreeMutations be used within public/, why not just forward-declare and
say "const cc::LayerTreeMutations&"? That class already has the same virtual
members. (It also avoids having to actually include the cc header, unlike
subclassing.) Ignore if a public OWNER overrules me. :)

[majidvp, 2016/01/25 20:40:11]

Done.
Happy to change if that is desirable. My impression after looking at recent
similar CLs
is that it is still desirable to define a type in Blink  by extending the CC
type [1].

[1]
https://chromium.googlesource.com/chromium/src/+/0536dbbcab956b879d2bee49f7e4...

+
     // Called to inform the WebWidget that mouse capture was lost.
     virtual void mouseCaptureLost() { }