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

content/browser/web_contents/web_contents_impl.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_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 620 matching lines @@
   // Changes the IsLoading state and notifies the delegate as needed.
   // |details| is used to provide details on the load that just finished
   // (but can be null if not applicable).
   void SetIsLoading(RenderViewHost* render_view_host,
                     bool is_loading,
                     bool to_different_document,
                     LoadNotificationDetails* details) override;
 
   typedef base::Callback<void(WebContents*)> CreatedCallback;
 
+  // Requests the renderer to move the selection extent to a new position.
+  void MoveRangeSelectionExtent(const gfx::Point& extent);
+
   // Requests the renderer to select the region between two points in the
   // currently focused frame.
-  void SelectRange(const gfx::Point& start, const gfx::Point& end);
+  void SelectRange(const gfx::Point& base, const gfx::Point& extent);
 
   // Notifies the main frame that it can continue navigation (if it was deferred
   // immediately at first response).
   void ResumeResponseDeferredAtStart();
 
   // Forces overscroll to be disabled (used by touch emulation).
   void SetForceDisableOverscrollContent(bool force_disable);
 
   AudioStreamMonitor* audio_stream_monitor() {
     return &audio_stream_monitor_;
@@ skipping 574 matching lines @@
   scoped_ptr<WebContentsAudioMuter> audio_muter_;
 
   base::WeakPtrFactory<WebContentsImpl> loading_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_