cc: Cleanup Layer::SetNeedsDisplayInRect

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 7fe86ac738f14900a6e9c1b34d7c0edfe118c076..70df6002d4e440a93b6c25c50ea85cf0c9fad282 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -620,13 +620,13 @@ void Layer::SetHideLayerAndSubtree(bool hide) {
 }
 
 void Layer::SetNeedsDisplayRect(const gfx::RectF& dirty_rect) {
+  if (dirty_rect.IsEmpty())

[slavi, 2013/07/11 21:58:09]

Don't do this. When I wrote that function, the intended semantics was that
dirty_rect will be appended to the region that need update. Passing empty rect
still should issue a commit.

See 
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/widget/de...
for example of such usage.

[danakj, 2013/07/11 21:59:12]

Why not just call SetNeedsCommit on the layer's host?

[tomhudson, 2013/07/24 09:02:43]

If people can't determine the intended semantics by reading the code, do we need
to add comments? Or more descriptive naming?

+    return;
+
   update_rect_.Union(dirty_rect);
   needs_display_ = true;
 
-  // Simply mark the contents as dirty. For non-root layers, the call to
-  // SetNeedsCommit will schedule a fresh compositing pass.
-  // For the root layer, SetNeedsCommit has no effect.
-  if (DrawsContent() && !update_rect_.IsEmpty())
+  if (DrawsContent())
     SetNeedsCommit();
 }