Check if Button is pressed for changing selection

content/browser/renderer_host/input/gesture_text_selector.cc

 // Copyright 2014 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 "content/browser/renderer_host/input/gesture_text_selector.h"
 
 #include "ui/events/event_constants.h"
 #include "ui/events/gesture_detection/gesture_event_data.h"
 #include "ui/events/gesture_detection/motion_event.h"
 
 namespace content {
 
 GestureTextSelector::GestureTextSelector(GestureTextSelectorClient* client)
     : client_(client),
       text_selection_triggered_(false),
+      secondary_button_pressed_(false),
       anchor_x_(0.0f),
       anchor_y_(0.0f) {
 }
 
 GestureTextSelector::~GestureTextSelector() {
 }
 
 bool GestureTextSelector::OnTouchEvent(const ui::MotionEvent& event) {
   if (event.GetAction() == ui::MotionEvent::ACTION_DOWN) {
     // Only trigger selection on ACTION_DOWN to prevent partial touch or gesture
     // sequences from being forwarded.
     text_selection_triggered_ = ShouldStartTextSelection(event);
   }
+  if (text_selection_triggered_ &&
+      event.GetAction() == ui::MotionEvent::ACTION_MOVE) {
+    secondary_button_pressed_ =
+        event.GetButtonState() == ui::MotionEvent::BUTTON_SECONDARY;
+  }
   return text_selection_triggered_;
 }
 
 bool GestureTextSelector::OnGestureEvent(const ui::GestureEventData& gesture) {
   if (!text_selection_triggered_)
     return false;
 
   switch (gesture.type()) {
     case ui::ET_GESTURE_TAP: {
       client_->LongPress(gesture.time, gesture.x, gesture.y);
       break;
     }
     case ui::ET_GESTURE_SCROLL_BEGIN: {
       client_->Unselect();
       anchor_x_ = gesture.x;
       anchor_y_ = gesture.y;
       break;
     }
     case ui::ET_GESTURE_SCROLL_UPDATE: {
       // TODO(changwan): check if we can show handles on ET_GESTURE_SCROLL_END
       // instead. Currently it is not possible as ShowSelectionHandles should
       // be called before we change the selection.
-      client_->ShowSelectionHandlesAutomatically();
-      client_->SelectRange(anchor_x_, anchor_y_, gesture.x, gesture.y);
+      if (secondary_button_pressed_) {

[jdduke (slow), 2014/09/23 15:10:48]

So, what happens when the user repeatedly presses/releases the button? We don't
adjust the anchor, so it seems like the selection will "jump" to the new stylus
location? Is that the intended result? Ideally we would match whatever the
native behavior is, e.g., should pressing the button again trigger a *new*
selection region instead of extending the previous one?

[AviD, 2014/09/23 16:01:04]

Yes, you are right. Triggering a new selection in this case is the ideal
behavior in case of using Stylus as mouse.

+        client_->ShowSelectionHandlesAutomatically();
+        client_->SelectRange(anchor_x_, anchor_y_, gesture.x, gesture.y);
+      }
       break;
     }
     default:
       // Suppress all other gestures when we are selecting text.
       break;
   }
   return true;
 }
 
 // static
 bool GestureTextSelector::ShouldStartTextSelection(
     const ui::MotionEvent& event) {
   DCHECK_GT(event.GetPointerCount(), 0u);
   // Currently we are supporting stylus-only cases.
   const bool is_stylus =
       event.GetToolType(0) == ui::MotionEvent::TOOL_TYPE_STYLUS;
   const bool is_only_secondary_button_pressed =
       event.GetButtonState() == ui::MotionEvent::BUTTON_SECONDARY;
   return is_stylus && is_only_secondary_button_pressed;
 }
 
 }  // namespace content