Make iframe's load event trigger a reflow of the enclosing window. Add a catch-all reflow for all same-origin pages sharing an event loop.a

components/script/dom/htmliframeelement.rs

@@ -23,9 +23,10 @@ use dom::htmlelement::HTMLElement;
 use dom::node::{Node, UnbindContext, window_from_node};
 use dom::urlhelper::UrlHelper;
 use dom::virtualmethods::VirtualMethods;
-use dom::window::Window;
+use dom::window::{ReflowReason, Window};
 use js::jsapi::{JSAutoCompartment, JSAutoRequest, RootedValue, JSContext, MutableHandleValue};
 use js::jsval::{UndefinedValue, NullValue};
+use layout_interface::ReflowQueryType;
 use msg::constellation_msg::{ConstellationChan};
 use msg::constellation_msg::{NavigationDirection, PipelineId, SubpageId};
 use page::IterablePage;
@@ -34,6 +35,7 @@ use script_traits::{IFrameLoadInfo, MozBrowserEvent, ScriptMsg as ConstellationM
 use std::ascii::AsciiExt;
 use std::cell::Cell;
 use string_cache::Atom;
+use style::context::ReflowGoal;
 use url::Url;
 use util::prefs;
 use util::str::{DOMString, LengthOrPercentageOrAuto};
@@ -211,6 +213,10 @@ impl HTMLIFrameElement {
         let window = window_from_node(self);
         self.upcast::<EventTarget>().fire_simple_event("load", GlobalRef::Window(window.r()));
         // TODO Step 5 - unset child document `mut iframe load` flag
+
+        window.reflow(ReflowGoal::ForDisplay,
+                      ReflowQueryType::NoQuery,
+                      ReflowReason::IFrameLoadEvent);
     }
 }
 

components/script/dom/window.rs

@@ -108,6 +108,8 @@ pub enum ReflowReason {
     RequestAnimationFrame,
     WebFontLoaded,
     FramedContentChanged,
+    IFrameLoadEvent,
+    MissingExplicitReflow,
 }
 
 pub type ScrollPoint = Point2D<Au>;
@@ -1427,6 +1429,8 @@ fn debug_reflow_events(goal: &ReflowGoal, query_type: &ReflowQueryType, reason:
         ReflowReason::RequestAnimationFrame => "\tRequestAnimationFrame",
         ReflowReason::WebFontLoaded => "\tWebFontLoaded",
         ReflowReason::FramedContentChanged => "\tFramedContentChanged",
+        ReflowReason::IFrameLoadEvent => "\tIFrameLoadEvent",
+        ReflowReason::MissingExplicitReflow => "\tMissingExplicitReflow",
     });
 
     println!("{}", debug_msg);

components/script/script_thread.rs

@@ -1028,6 +1028,14 @@ impl ScriptThread {
                     window.reflow(ReflowGoal::ForDisplay,
                                   ReflowQueryType::NoQuery,
                                   ReflowReason::ImageLoaded);
+                } else {
+                    // Reflow currently happens when explicitly invoked by code that
+                    // knows the document could have been modified. This should really
+                    // be driven by the compositor on an as-needed basis instead, to
+                    // minimize unnecessary work.
+                    window.reflow(ReflowGoal::ForDisplay,
+                                  ReflowQueryType::NoQuery,
+                                  ReflowReason::MissingExplicitReflow);
                 }
             }
         }