aura: Try to make Linux host resize code more reliable.

ui/aura/desktop.h

Index: ui/aura/desktop.h
diff --git a/ui/aura/desktop.h b/ui/aura/desktop.h
index 34e47eef4e34fc6b2bddc5e943071e998fb045a1..a843ba2137d078d392d64416f5580c76156b1254 100644
--- a/ui/aura/desktop.h
+++ b/ui/aura/desktop.h
@@ -69,7 +69,9 @@ class AURA_EXPORT Desktop : public ui::CompositorDelegate,
   // Shows the desktop host.
   void ShowDesktop();
 
-  // Sets the size of the desktop.
+  // Sets the size of the desktop.  Note that in some implementations (i.e.
+  // X11), resizing happens asynchronously, so a size passed to SetHostSize()
+  // may not be immediately reflected in GetHostSize().

[sadrul, 2011/10/22 18:53:04]

I dislike this part of the change.

I confirmed that, with at least ion3, a Desktop->SetHostSize triggers a
ConfigureNotify event, even though it ignores the resize request. I think we
should either keep the current behaviour (this would be my preference), or wait
for ConfigureNotify before returning from SetSize.

[Daniel Erat, 2011/10/23 04:02:55]

I'm in favor of waiting for the ConfigureNotify before returning (since keeping
the current behavior means that we're confused about our size for a period of
time).  ICCCM requires that WMs send a synthetic ConfigureNotify even if they
ignore the request IIRC; I just wasn't sure if that was another part of the spec
that Tuomo disagreed with. :-P

   void SetHostSize(const gfx::Size& size);
   gfx::Size GetHostSize() const;