[Android] Introduce state machine in stylus text selection

content/browser/renderer_host/input/stylus_text_selector.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_STYLUS_TEXT_SELECTOR_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_STYLUS_TEXT_SELECTOR_H_
 
 #include <memory>
 
 #include "base/gtest_prod_util.h"
@@ skipping 32 matching lines @@
 class CONTENT_EXPORT StylusTextSelector : public ui::SimpleGestureListener {
  public:
   explicit StylusTextSelector(StylusTextSelectorClient* client);
   ~StylusTextSelector() override;
 
   // This should be called before |event| is seen by the platform gesture
   // detector or forwarded to web content.
   bool OnTouchEvent(const ui::MotionEvent& event);
 
  private:
+  enum DragState {
+    NO_DRAG,
+    DRAGGING_WITH_BUTTON_PRESSED,
+    DRAGGING_WITH_BUTTON_RELEASED,
+  };
   friend class StylusTextSelectorTest;
   FRIEND_TEST_ALL_PREFIXES(StylusTextSelectorTest, ShouldStartTextSelection);
 
   // SimpleGestureListener implementation.
   bool OnSingleTapUp(const ui::MotionEvent& e, int tap_count) override;
   bool OnScroll(const ui::MotionEvent& e1,
                 const ui::MotionEvent& e2,
                 const ui::MotionEvent& secondary_pointer_down,
                 float distance_x,
                 float distance_y) override;
 
   static bool ShouldStartTextSelection(const ui::MotionEvent& event);
 
   StylusTextSelectorClient* client_;
   bool text_selection_triggered_;
   bool secondary_button_pressed_;
-  bool dragging_;
-  bool dragged_;
+  DragState drag_state_;
   float anchor_x_;
   float anchor_y_;
   std::unique_ptr<ui::GestureDetector> gesture_detector_;
 
   DISALLOW_COPY_AND_ASSIGN(StylusTextSelector);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_STYLUS_TEXT_SELECTOR_H_