Implemented smooth scrolling using xinput2 in X11.

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 1197 matching lines @@
   // the WebContents creation time.
   base::TimeTicks last_active_time_;
 
   // See description above setter.
   bool closed_by_user_gesture_;
 
   // Minimum/maximum zoom percent.
   int minimum_zoom_percent_;
   int maximum_zoom_percent_;
 
+  // Used to correctly handle integer zooming through a smooth scroll device.
+  float zoom_scroll_amount_;

[bokan, 2015/12/01 18:29:27]

Please initialize this

+
   // The intrinsic size of the page.
   gfx::Size preferred_size_;
 
   // The preferred size for content screen capture.  When |capturer_count_| > 0,
   // this overrides |preferred_size_|.
   gfx::Size preferred_size_for_capture_;
 
 #if defined(OS_ANDROID) && !defined(USE_AURA)
   // Date time chooser opened by this tab.
   // Only used in Android since all other platforms use a multi field UI.
@@ skipping 125 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_