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

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 1315 matching lines @@
                     GURL /* document_url */,
                     base::FilePath /* plugin_path */)
 #endif  // defined(ENABLE_PLUGINS)
 
 // Send the tooltip text for the current mouse position to the browser.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_SetTooltipText,
                     base::string16 /* tooltip text string */,
                     blink::WebTextDirection /* text direction hint */)
 
 IPC_MESSAGE_ROUTED0(ViewHostMsg_SelectRange_ACK)
+IPC_MESSAGE_ROUTED0(ViewHostMsg_MoveSelectionExtent_ACK)

[jdduke (slow), 2014/10/15 15:46:07]

Hmm, these should really be InputHostMsg types, would you mind moving them into
input_messages.h (and updating input_router_impl.cc/render_frame_impl.cc
accordingly)? Thanks.

[christiank, 2014/10/17 14:33:05]

Sure!

 IPC_MESSAGE_ROUTED0(ViewHostMsg_MoveCaret_ACK)
 
 // Notification that the text selection has changed.
 // Note: The secound parameter is the character based offset of the
 // base::string16
 // text in the document.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_SelectionChanged,
                     base::string16 /* text covers the selection range */,
                     size_t /* the offset of the text in the document */,
                     gfx::Range /* selection range in the document */)
@@ skipping 297 matching lines @@
 // Since the browser keeps handles to the allocated transport DIBs, this
 // message is sent to tell the browser that it may release them when the
 // renderer is finished with them.
 IPC_MESSAGE_CONTROL1(ViewHostMsg_FreeTransportDIB,
                      TransportDIB::Id /* DIB id */)
 #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.