Update touch selection to only modify one selection point at a time.

content/browser/renderer_host/render_widget_host_view_android.h

 // Copyright (c) 2012 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_RENDER_WIDGET_HOST_VIEW_ANDROID_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_ANDROID_H_
 
 #include <map>
 #include <queue>
 
@@ skipping 245 matching lines @@
       void(const base::string16& content, int start_offset, int end_offset)>
       TextSurroundingSelectionCallback;
   void SetTextSurroundingSelectionCallback(
       const TextSurroundingSelectionCallback& callback);
 
  private:
   // TouchSelectionControllerClient implementation.
   virtual bool SupportsAnimation() const override;
   virtual void SetNeedsAnimate() override;
   virtual void MoveCaret(const gfx::PointF& position) override;
+  virtual void MoveSelectionExtent(const gfx::PointF& position) override;
   virtual void SelectBetweenCoordinates(const gfx::PointF& start,
                                         const gfx::PointF& end) override;
   virtual void OnSelectionEvent(SelectionEventType event,
                                 const gfx::PointF& anchor_position) override;
   virtual scoped_ptr<TouchHandleDrawable> CreateDrawable() override;
 
   void RunAckCallbacks();
 
   void DestroyDelegatedContent();
   void SwapDelegatedFrame(uint32 output_surface_id,
@@ skipping 138 matching lines @@
   gfx::Vector2dF last_scroll_offset_;
 
   base::WeakPtrFactory<RenderWidgetHostViewAndroid> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAndroid);
 };
 
 } // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_ANDROID_H_