Bug 926389 - Add touch event handling during fluffing. r=roc

layout/base/PositionedEventTargeting.cpp

@@ -127,6 +127,31 @@ HasMouseListener(nsIContent* aContent)
          elm->HasListenersFor(nsGkAtoms::onmouseup);
 }
 
+static bool gTouchEventsRegistered = false;
+static int32_t gTouchEventsEnabled = 0;
+
+static bool
+HasTouchListener(nsIContent* aContent)
+{
+  nsEventListenerManager* elm = aContent->GetListenerManager(false);
+  if (!elm) {
+    return false;
+  }
+
+  if (!gTouchEventsRegistered) {
+    Preferences::AddIntVarCache(&gTouchEventsEnabled,
+      "dom.w3c_touch_events.enabled", gTouchEventsEnabled);
+    gTouchEventsRegistered = true;
+  }
+
+  if (!gTouchEventsEnabled) {
+    return false;
+  }
+
+  return elm->HasListenersFor(nsGkAtoms::ontouchstart) ||
+         elm->HasListenersFor(nsGkAtoms::ontouchend);
+}
+
 static bool
 IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr)
 {
@@ -138,7 +163,7 @@ IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr)
     if (content->IsHTML() && stopAt && tag == stopAt) {
       break;
     }
-    if (HasMouseListener(content)) {
+    if (HasTouchListener(content) || HasMouseListener(content)) {
       return true;
     }
     if (content->IsHTML()) {

layout/base/tests/test_event_target_radius.html

@@ -45,6 +45,8 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=780847
 
   <div id="t8" contenteditable="true" class="target" hidden></div>
 
+  <div id="t9" class="target" ontouchend="x=1" hidden></div>
+
 </div>
 <pre id="test">
 <script type="application/javascript">
@@ -203,6 +205,15 @@ function test3() {
   });
   setShowing("t8", false);
 
+  // Check that elements are touchable
+  setShowing("t9", true);
+  var rect = document.getElementById("t9").getBoundingClientRect();
+  testMouseClick("t9", rect.left + 1, rect.top + 1, "t9", "div enabled with mouse input");
+  testMouseClick("t9", rect.left + 1, rect.top + 1, "t9", "div enabled with touch input", {
+    inputSource: SpecialPowers.Ci.nsIDOMMouseEvent.MOZ_SOURCE_TOUCH
+  });
+  setShowing("t9", false);
+
   // Not yet tested:
   // -- visited link weight
   // -- "Closest" using Euclidean distance