VR: Sending the fling event to the right target

Fling event is sent to the same target that the last scroll event
was sent to.

BUG=698260

Review-Url: https://codereview.chromium.org/2808723003
Cr-Commit-Position: refs/heads/master@{#464419}

chrome/browser/android/vr_shell/vr_shell_gl.cc

@@ -727,25 +727,37 @@ void VrShellGl::SendEventsToTarget(InputTarget input_target,
       // Once the user starts scrolling send all the scroll events to this
       // element until the scrolling stops.
       case WebInputEvent::kGestureScrollBegin:
-        current_scroll_target = input_target;
-        if (current_scroll_target != InputTarget::NONE) {
-          SendGesture(current_scroll_target, std::move(movableGesture));
+        current_scroll_target_ = input_target;
+        if (current_scroll_target_ != InputTarget::NONE) {
+          SendGesture(current_scroll_target_, std::move(movableGesture));
         }
         break;
       case WebInputEvent::kGestureScrollEnd:
-        if (current_scroll_target != InputTarget::NONE) {
-          SendGesture(current_scroll_target, std::move(movableGesture));
+        if (current_scroll_target_ != InputTarget::NONE) {
+          SendGesture(current_scroll_target_, std::move(movableGesture));
         }
-        current_scroll_target = InputTarget::NONE;
+        current_fling_target_ = current_scroll_target_;
+        current_scroll_target_ = InputTarget::NONE;
         break;
       case WebInputEvent::kGestureScrollUpdate:
-      case WebInputEvent::kGestureFlingCancel:
+        if (current_scroll_target_ != InputTarget::NONE) {
+          SendGesture(current_scroll_target_, std::move(movableGesture));
+        }
+        break;
       case WebInputEvent::kGestureFlingStart:
-        if (current_scroll_target != InputTarget::NONE) {
-          SendGesture(current_scroll_target, std::move(movableGesture));
+        if (current_fling_target_ != InputTarget::NONE) {
+          SendGesture(current_fling_target_, std::move(movableGesture));
+        }
+        current_fling_target_ = InputTarget::NONE;
+        break;
+      case WebInputEvent::kGestureFlingCancel:
+        current_fling_target_ = InputTarget::NONE;
+        if (input_target != InputTarget::NONE) {
+          SendGesture(input_target, std::move(movableGesture));
         }
         break;
       case WebInputEvent::kGestureTapDown:
+        current_fling_target_ = InputTarget::NONE;
         if (input_target != InputTarget::NONE) {
           SendGesture(input_target, std::move(movableGesture));
         }

chrome/browser/android/vr_shell/vr_shell_gl.h

@@ -200,7 +200,8 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   gfx::Point3F target_point_;
   const UiElement* target_element_ = nullptr;
   InputTarget current_input_target_ = InputTarget::NONE;
-  InputTarget current_scroll_target = InputTarget::NONE;
+  InputTarget current_scroll_target_ = InputTarget::NONE;
+  InputTarget current_fling_target_ = InputTarget::NONE;
   int ui_tex_css_width_ = 0;
   int ui_tex_css_height_ = 0;
   int content_tex_css_width_ = 0;