Send touch events to root pipeline, and allow forwarding to iframes.

Instead of letting the compositor try to find the correct scroll
layer for a touch event, switch touch events to work the same way
that mouse events do.

Touch events are now dispatched to the root pipeline, and then
forwarded to child iframes as required.

components/script/dom/document.rs

@@ -106,7 +106,7 @@ use origin::Origin;
 use parse::{MutNullableParserField, ParserRef, ParserRoot};
 use script_layout_interface::message::{Msg, ReflowQueryType};
 use script_thread::{MainThreadScriptMsg, Runnable};
-use script_traits::{AnimationState, MouseButton, MouseEventType, MozBrowserEvent};
+use script_traits::{AnimationState, CompositorEvent, MouseButton, MouseEventType, MozBrowserEvent};
 use script_traits::{ScriptMsg as ConstellationMsg, TouchpadPressurePhase};
 use script_traits::{TouchEventType, TouchId};
 use script_traits::UntrustedNodeAddress;
@@ -133,6 +133,11 @@ use url::Url;
 use url::percent_encoding::percent_decode;
 use util::prefs::PREFS;
 
+pub enum TouchEventResult {
+    Processed(bool),
+    Forwarded,
+}
+
 #[derive(JSTraceable, PartialEq, HeapSizeOf)]
 pub enum IsHTMLDocument {
     HTMLDocument,
@@ -723,9 +728,8 @@ impl Document {
                 let child_origin = Point2D::new(rect.X() as f32, rect.Y() as f32);
                 let child_point = client_point - child_origin;
 
-                let event = ConstellationMsg::ForwardMouseButtonEvent(pipeline_id,
-                                                                      mouse_event_type,
-                                                                      button, child_point);
+                let event = CompositorEvent::MouseButtonEvent(mouse_event_type, button, child_point);
+                let event = ConstellationMsg::ForwardEvent(pipeline_id, event);
                 self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
             }
             return;
@@ -853,14 +857,6 @@ impl Document {
                                           client_point: Point2D<f32>,
                                           pressure: f32,
                                           phase_now: TouchpadPressurePhase) {
-        let phase_before = self.touchpad_pressure_phase.get();
-        self.touchpad_pressure_phase.set(phase_now);
-
-        if phase_before == TouchpadPressurePhase::BeforeClick &&
-           phase_now == TouchpadPressurePhase::BeforeClick {
-            return;
-        }
-
         let node = match self.window.hit_test_query(client_point, false) {
             Some(node_address) => node::from_untrusted_node_address(js_runtime, node_address),
             None => return
@@ -877,6 +873,30 @@ impl Document {
             },
         };
 
+        // If the target is an iframe, forward the event to the child document.
+        if let Some(iframe) = el.downcast::<HTMLIFrameElement>() {
+            if let Some(pipeline_id) = iframe.pipeline_id() {
+                let rect = iframe.upcast::<Element>().GetBoundingClientRect();
+                let child_origin = Point2D::new(rect.X() as f32, rect.Y() as f32);
+                let child_point = client_point - child_origin;
+
+                let event = CompositorEvent::TouchpadPressureEvent(child_point,
+                                                                   pressure,
+                                                                   phase_now);
+                let event = ConstellationMsg::ForwardEvent(pipeline_id, event);
+                self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
+            }
+            return;
+        }
+
+        let phase_before = self.touchpad_pressure_phase.get();
+        self.touchpad_pressure_phase.set(phase_now);
+
+        if phase_before == TouchpadPressurePhase::BeforeClick &&
+           phase_now == TouchpadPressurePhase::BeforeClick {
+            return;
+        }
+
         let node = el.upcast::<Node>();
         let target = node.upcast();
 
@@ -963,7 +983,8 @@ impl Document {
                     let child_origin = Point2D::new(rect.X() as f32, rect.Y() as f32);
                     let child_point = client_point - child_origin;
 
-                    let event = ConstellationMsg::ForwardMouseMoveEvent(pipeline_id, child_point);
+                    let event = CompositorEvent::MouseMoveEvent(Some(child_point));
+                    let event = ConstellationMsg::ForwardEvent(pipeline_id, event);
                     self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
                 }
                 return;
@@ -1032,9 +1053,11 @@ impl Document {
     pub fn handle_touch_event(&self,
                               js_runtime: *mut JSRuntime,
                               event_type: TouchEventType,
-                              TouchId(identifier): TouchId,
+                              touch_id: TouchId,
                               point: Point2D<f32>)
-                              -> bool {
+                              -> TouchEventResult {
+        let TouchId(identifier) = touch_id;
+
         let event_name = match event_type {
             TouchEventType::Down => "touchstart",
             TouchEventType::Move => "touchmove",
@@ -1044,7 +1067,7 @@ impl Document {
 
         let node = match self.window.hit_test_query(point, false) {
             Some(node_address) => node::from_untrusted_node_address(js_runtime, node_address),
-            None => return false,
+            None => return TouchEventResult::Processed(false),
         };
         let el = match node.downcast::<Element>() {
             Some(el) => Root::from_ref(el),
@@ -1052,10 +1075,25 @@ impl Document {
                 let parent = node.GetParentNode();
                 match parent.and_then(Root::downcast::<Element>) {
                     Some(parent) => parent,
-                    None => return false,
+                    None => return TouchEventResult::Processed(false),
                 }
             },
         };
+
+        // If the target is an iframe, forward the event to the child document.
+        if let Some(iframe) = el.downcast::<HTMLIFrameElement>() {
+            if let Some(pipeline_id) = iframe.pipeline_id() {
+                let rect = iframe.upcast::<Element>().GetBoundingClientRect();
+                let child_origin = Point2D::new(rect.X() as f32, rect.Y() as f32);
+                let child_point = point - child_origin;
+
+                let event = CompositorEvent::TouchEvent(event_type, touch_id, child_point);
+                let event = ConstellationMsg::ForwardEvent(pipeline_id, event);
+                self.window.upcast::<GlobalScope>().constellation_chan().send(event).unwrap();
+            }
+            return TouchEventResult::Forwarded;
+        }
+
         let target = Root::upcast::<EventTarget>(el);
         let window = &*self.window;
 
@@ -1132,8 +1170,8 @@ impl Document {
                       ReflowReason::MouseEvent);
 
         match result {
-            EventStatus::Canceled => false,
-            EventStatus::NotCanceled => true
+            EventStatus::Canceled => TouchEventResult::Processed(false),
+            EventStatus::NotCanceled => TouchEventResult::Processed(true),
         }
     }