Fail if key synthesized events are off screen.

content/browser/renderer_host/input/synthetic_gesture_target_base.cc

Index: content/browser/renderer_host/input/synthetic_gesture_target_base.cc
diff --git a/content/browser/renderer_host/input/synthetic_gesture_target_base.cc b/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
index 778afb0d4f5d044a178968648889739e55715342..b10660c33ca385d7ab33a795629700149704ef7d 100644
--- a/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
+++ b/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
@@ -52,14 +52,28 @@ void SyntheticGestureTargetBase::DispatchInputEventToPlatform(
   if (WebInputEvent::isTouchEventType(event.type)) {
     const WebTouchEvent& web_touch =
         static_cast<const WebTouchEvent&>(event);
+
+    // Check that all touch pointers are on the screen on TouchStart.
+    if (web_touch.type == WebInputEvent::TouchStart) {
+      for (unsigned i = 0; i < web_touch.touchesLength; i++)

[jdduke (slow), 2014/04/28 16:30:23]

It's probably only necessary to check touch positions for which
|web_touch.touches[i].state == WebTouchPoint::StatePressed|.

[Dominik Grewe, 2014/04/28 17:32:24]

Done.

+        CHECK(PointIsOnScreen(web_touch.touches[i].screenPosition.x,

[Rick Byers, 2014/04/28 17:01:22]

The fact that you're using screenPosition (instead of position) here seems
inconsistent with the OffsetFromOrigin call below (if these are really scree
co-ordinates then you should be able to treat them as such instead of treating
them like window co-ordiates).  I don't think we're consistent with how we use
screenPosition for synthetic events - we're probably sometimes actually storing
window co-ords here (at least SyntheticGestureTargetAura seems to assume that in
case cases).

I suggest you validate the window-relative co-ords in 'position' instead.

[Dominik Grewe, 2014/04/28 17:32:24]

Done.

+                              web_touch.touches[i].screenPosition.y))
+            << "Touch coordinates are off screen on TouchStart.";
+    }
+
     DispatchWebTouchEventToPlatform(web_touch, latency_info);
   } else if (event.type == WebInputEvent::MouseWheel) {
     const WebMouseWheelEvent& web_wheel =
         static_cast<const WebMouseWheelEvent&>(event);
+    CHECK(PointIsOnScreen(web_wheel.x, web_wheel.y))
+        << "Mouse wheel position is off screen.";
     DispatchWebMouseWheelEventToPlatform(web_wheel, latency_info);
   } else if (WebInputEvent::isMouseEventType(event.type)) {
     const WebMouseEvent& web_mouse =
         static_cast<const WebMouseEvent&>(event);
+    CHECK(event.type != WebInputEvent::MouseDown ||
+          PointIsOnScreen(web_mouse.x, web_mouse.y))
+        << "Mouse pointer is off screen on MouseDown.";
     DispatchWebMouseEventToPlatform(web_mouse, latency_info);
   } else {
     NOTREACHED();
@@ -72,7 +86,7 @@ void SyntheticGestureTargetBase::DispatchWebTouchEventToPlatform(
   // We assume that platforms supporting touch have their own implementation of
   // SyntheticGestureTarget to route the events through their respective input
   // stack.
-  CHECK(false);
+  CHECK(false) << "Touch events not supported for this browser.";
 }
 
 void SyntheticGestureTargetBase::DispatchWebMouseWheelEventToPlatform(
@@ -105,4 +119,10 @@ int SyntheticGestureTargetBase::GetTouchSlopInDips() const {
   return kTouchSlopInDips;
 }
 
+bool SyntheticGestureTargetBase::PointIsOnScreen(int x, int y) const {

[Rick Byers, 2014/04/28 17:01:22]

You mean "within contents" not "on screen" I think (this distinction is probably
less relevant on Android, but on Aura Screen != Window != contents area).

[Dominik Grewe, 2014/04/28 17:32:24]

Done.

+  gfx::Rect bounds = host_->GetView()->GetViewBounds();

[Rick Byers, 2014/04/28 17:01:22]

GetViewBounds says it's relative to the parent, I think you want
GetContainerBounds instead (which are in screen co-ordinates).  Or if you're
validating window-relative co-ordinates then you can jus use GetContainerSize.

[jdduke (slow), 2014/04/28 17:16:09]

Is GetViewBounds().size() equivalent to GetContainerSize()?

+  bounds -= bounds.OffsetFromOrigin();  // Translate the bounds to (0,0).

[jdduke (slow), 2014/04/28 16:30:23]

Are the bounds in device pixels or DIPs?

[Dominik Grewe, 2014/04/28 16:38:46]

Good question... In the comments it says "screen coordinates", not sure if
that's device or DIPs.

+  return bounds.Contains(x, y);
+}
+
 }  // namespace content