Scroll offset pinning and content size notifications were only used for the Mac overlay navigation …

content/common/view_messages.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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 1270 matching lines @@
 // Notifies that the preferred size of the content changed.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_DidContentsPreferredSizeChange,
                     gfx::Size /* pref_size */)
 
 // Notifies that the scroll offset changed.
 // This is different from ViewHostMsg_UpdateRect in that ViewHostMsg_UpdateRect
 // is not sent at all when threaded compositing is enabled while
 // ViewHostMsg_DidChangeScrollOffset works properly in this case.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_DidChangeScrollOffset)
 
-// Notifies that the pinned-to-side state of the content changed.
-IPC_MESSAGE_ROUTED2(ViewHostMsg_DidChangeScrollOffsetPinningForMainFrame,
-                    bool /* pinned_to_left */,
-                    bool /* pinned_to_right */)
-
 // Notifies whether there are JavaScript touch event handlers or not.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_HasTouchEventHandlers,
                     bool /* has_handlers */)
 
 // A message from HTML-based UI.  When (trusted) Javascript calls
 // send(message, args), this message is sent to the browser.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_WebUISend,
                     GURL /* source_url */,
                     std::string  /* message */,
                     base::ListValue /* args */)
@@ skipping 372 matching lines @@
                            uint32 /* font id */)
 
 // Informs the browser that a plugin has gained or lost focus.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_PluginFocusChanged,
                     bool, /* focused */
                     int /* plugin_id */)
 
 // Instructs the browser to start plugin IME.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_StartPluginIme)
 
-// Notifies that the scrollbars-visible state of the content changed.
-IPC_MESSAGE_ROUTED2(ViewHostMsg_DidChangeScrollbarsForMainFrame,
-                    bool /* has_horizontal_scrollbar */,
-                    bool /* has_vertical_scrollbar */)
-
 #elif defined(OS_WIN)
 // Request that the given font characters be loaded by the browser so it's
 // cached by the OS. Please see RenderMessageFilter::OnPreCacheFontCharacters
 // for details.
 IPC_SYNC_MESSAGE_CONTROL2_0(ViewHostMsg_PreCacheFontCharacters,
                             LOGFONT /* font_data */,
                             base::string16 /* characters */)
 #endif
 
 #if defined(OS_POSIX)
@@ skipping 22 matching lines @@
 // synchronously (see crbug.com/120597). This IPC message sends the character
 // bounds after every composition change to always have correct bound info.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ImeCompositionRangeChanged,
                     gfx::Range /* composition range */,
                     std::vector<gfx::Rect> /* character bounds */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.