Refactoring to make adding ink drop animations easier

ui/views/animation/toolbar_ink_drop_delegate.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/events/event.h"
+#include "ui/views/animation/ink_drop_animation_controller.h"
+#include "ui/views/animation/ink_drop_state.h"
+#include "ui/views/animation/toolbar_ink_drop_delegate.h"
+
+namespace views {
+
+ToolbarInkDropDelegate::ToolbarInkDropDelegate(
+    InkDropAnimationController* ink_drop_animation_controller)
+  : ink_drop_animation_controller_(ink_drop_animation_controller) {
+}
+
+ToolbarInkDropDelegate::~ToolbarInkDropDelegate() {
+}
+
+void ToolbarInkDropDelegate::OnGestureEvent(ui::GestureEvent* event) {

[bruthig, 2015/11/06 20:29:11]

Just re-iterating my quick parting comments from when we brainstormed solutions
for this.
Most of this event handling log must already exist somewhere. i.e. Within the
ToolbarActionView -> ... -> View hierarchy. To be candid, I really think it's a
bad decision if we duplicated it between there and an InkDropDelegate hierarchy.
 This distributed logic is hard to understand, get right, and maintain to be
equivalent between the two hierarchies. We've already got a yo-yo like event
handling mechanism with the Pre/Post target handlers and then the actual Views
handling.  We would now be adding yet another up/down handling of the event.

[varkha, 2015/11/06 20:51:50]

Maybe. This however allows to refactor what we have now with less code
duplication and then possibly address the cases where the two hierarchies are
too coupled.

+  views::InkDropState ink_drop_state = views::InkDropState::HIDDEN;
+  LOG(ERROR) << __FUNCTION__ << " event:" << event->type();
+  switch (event->type()) {
+    case ui::ET_GESTURE_TAP_DOWN:
+      ink_drop_state = views::InkDropState::ACTION_PENDING;
+      // The ui::ET_GESTURE_TAP_DOWN event needs to be marked as handled so that
+      // subsequent events for the gesture are sent to |this|.
+      event->SetHandled();
+      break;
+    case ui::ET_GESTURE_LONG_PRESS:
+      ink_drop_state = views::InkDropState::SLOW_ACTION_PENDING;
+      break;
+    case ui::ET_GESTURE_LONG_TAP:
+      ink_drop_state = views::InkDropState::SLOW_ACTION;
+      break;
+    case ui::ET_GESTURE_SCROLL_BEGIN:
+    case ui::ET_GESTURE_END:
+      ink_drop_state = views::InkDropState::HIDDEN;
+      break;
+    default:
+      return;
+  }
+
+  views::InkDropState current_ink_drop_state =
+      ink_drop_animation_controller_->GetInkDropState();
+
+  if (ink_drop_state == views::InkDropState::HIDDEN &&
+      (current_ink_drop_state == views::InkDropState::QUICK_ACTION ||
+       current_ink_drop_state == views::InkDropState::SLOW_ACTION ||
+       current_ink_drop_state == views::InkDropState::DEACTIVATED)) {
+    // These InkDropStates automatically transition to the HIDDEN state so we
+    // don't make an explicit call. Explicitly animating to HIDDEN in this case
+    // would prematurely pre-empt these animations.
+    return;
+  }
+  LOG(ERROR) << __FUNCTION__ << " state:" << (int)ink_drop_state;
+  ink_drop_animation_controller_->AnimateToState(ink_drop_state);
+}
+
+}  // namespace views