[WIP] Allow scroll events to permanently change the default gesture handler in RootView

chrome/browser/ui/views/tabs/tab.cc

Index: chrome/browser/ui/views/tabs/tab.cc
diff --git a/chrome/browser/ui/views/tabs/tab.cc b/chrome/browser/ui/views/tabs/tab.cc
index 20b7abeecc685ba1a0204298b8514825ae953e65..f501fdd54b98b4be1308697e59ab1be235ad6470 100644
--- a/chrome/browser/ui/views/tabs/tab.cc
+++ b/chrome/browser/ui/views/tabs/tab.cc
@@ -423,7 +423,7 @@ Tab::Tab(TabController* controller)
       animating_media_state_(TAB_MEDIA_STATE_NONE),
       close_button_(NULL),
       title_(new views::Label()),
-      tab_activated_with_last_gesture_begin_(false),
+      tab_activated_with_last_tap_down_(false),
       hover_controller_(this),
       showing_icon_(false),
       showing_media_indicator_(false),
@@ -975,7 +975,7 @@ void Tab::OnMouseExited(const ui::MouseEvent& event) {
 
 void Tab::OnGestureEvent(ui::GestureEvent* event) {
   switch (event->type()) {
-    case ui::ET_GESTURE_BEGIN: {
+    case ui::ET_GESTURE_TAP_DOWN: {
       if (event->details().touch_points() != 1)

[tdanderson, 2014/07/24 18:07:21]

This is always true for TAP_DOWN, right?

[tdresser, 2014/07/24 18:17:23]

Yeah, you can safely remove this early-out.

         return;
 
@@ -984,7 +984,7 @@ void Tab::OnGestureEvent(ui::GestureEvent* event) {
                                        parent());
       ui::ListSelectionModel original_selection;
       original_selection.Copy(controller_->GetSelectionModel());
-      tab_activated_with_last_gesture_begin_ = !IsActive();
+      tab_activated_with_last_tap_down_ = !IsActive();
       if (!IsSelected())
         controller_->SelectTab(this);
       gfx::Point loc(event->location());
@@ -995,7 +995,8 @@ void Tab::OnGestureEvent(ui::GestureEvent* event) {
       break;
     }
 
-    case ui::ET_GESTURE_END:
+    case ui::ET_GESTURE_SCROLL_END:
+    case ui::ET_SCROLL_FLING_START:
       controller_->EndDrag(END_DRAG_COMPLETE);
       break;