This is the exact same CL as in http://codereview.chromium.org/7570001 .

content/renderer/render_view.cc

 // Copyright (c) 2011 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.
 
 #include "content/renderer/render_view.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 343 matching lines @@
       target_url_status_(TARGET_NONE),
       ALLOW_THIS_IN_INITIALIZER_LIST(pepper_delegate_(this)),
       ALLOW_THIS_IN_INITIALIZER_LIST(accessibility_method_factory_(this)),
       ALLOW_THIS_IN_INITIALIZER_LIST(cookie_jar_(this)),
       geolocation_dispatcher_(NULL),
       speech_input_dispatcher_(NULL),
       device_orientation_dispatcher_(NULL),
       accessibility_ack_pending_(false),
       p2p_socket_dispatcher_(NULL),
       devtools_agent_(NULL),
-      session_storage_namespace_id_(session_storage_namespace_id) {
+      session_storage_namespace_id_(session_storage_namespace_id),
+      handling_select_range_(false) {
   routing_id_ = routing_id;
   if (opener_id != MSG_ROUTING_NONE)
     opener_id_ = opener_id;
 
   webwidget_ = WebView::create(this);
 
   if (counter) {
     shared_popup_counter_ = counter;
     shared_popup_counter_->data++;
     decrement_shared_popup_at_destruction_ = true;
@@ skipping 232 matching lines @@
     IPC_MESSAGE_HANDLER(ViewMsg_Redo, OnRedo)
     IPC_MESSAGE_HANDLER(ViewMsg_Cut, OnCut)
     IPC_MESSAGE_HANDLER(ViewMsg_Copy, OnCopy)
 #if defined(OS_MACOSX)
     IPC_MESSAGE_HANDLER(ViewMsg_CopyToFindPboard, OnCopyToFindPboard)
 #endif
     IPC_MESSAGE_HANDLER(ViewMsg_Paste, OnPaste)
     IPC_MESSAGE_HANDLER(ViewMsg_Replace, OnReplace)
     IPC_MESSAGE_HANDLER(ViewMsg_Delete, OnDelete)
     IPC_MESSAGE_HANDLER(ViewMsg_SelectAll, OnSelectAll)
+    IPC_MESSAGE_HANDLER(ViewMsg_SelectRange, OnSelectRange)
     IPC_MESSAGE_HANDLER(ViewMsg_CopyImageAt, OnCopyImageAt)
     IPC_MESSAGE_HANDLER(ViewMsg_ExecuteEditCommand, OnExecuteEditCommand)
     IPC_MESSAGE_HANDLER(ViewMsg_Find, OnFind)
     IPC_MESSAGE_HANDLER(ViewMsg_StopFinding, OnStopFinding)
     IPC_MESSAGE_HANDLER(ViewMsg_FindReplyACK, OnFindReplyAck)
     IPC_MESSAGE_HANDLER(ViewMsg_Zoom, OnZoom)
     IPC_MESSAGE_HANDLER(ViewMsg_SetZoomLevel, OnSetZoomLevel)
     IPC_MESSAGE_HANDLER(ViewMsg_SetZoomLevelForLoadingURL,
                         OnSetZoomLevelForLoadingURL)
     IPC_MESSAGE_HANDLER(ViewMsg_SetPageEncoding, OnSetPageEncoding)
@@ skipping 345 matching lines @@
 }
 
 void RenderView::OnSelectAll() {
   if (!webview())
     return;
 
   webview()->focusedFrame()->executeCommand(
       WebString::fromUTF8("SelectAll"));
 }
 
+void RenderView::OnSelectRange(const gfx::Point& start, const gfx::Point& end) {
+  if (!webview())
+    return;
+
+  handling_select_range_ = true;
+  webview()->focusedFrame()->selectRange(start, end);
+  handling_select_range_ = false;
+}
+
 void RenderView::OnSetInitialFocus(bool reverse) {
   if (!webview())
     return;
   webview()->setInitialFocus(reverse);
 }
 
 #if defined(OS_MACOSX)
 void RenderView::OnSetInLiveResize(bool in_live_resize) {
     if (!webview())
         return;
@@ skipping 516 matching lines @@
 bool RenderView::isSelectTrailingWhitespaceEnabled() {
 #if defined(OS_WIN)
   return true;
 #else
   return false;
 #endif
 }
 
 void RenderView::didChangeSelection(bool is_empty_selection) {
 #if defined(OS_POSIX)
-  if (!handling_input_event_)
+  if (!handling_input_event_ && !handling_select_range_)
       return;
+  handling_select_range_ = false;
 
   if (is_empty_selection) {
     last_selection_.clear();
   } else {
     // Sometimes we get repeated didChangeSelection calls from webkit when
     // the selection hasn't actually changed. We don't want to report these
     // because it will cause us to continually claim the X clipboard.
     WebFrame* frame = webview()->focusedFrame();
     const std::string& this_selection = frame->selectionAsText().utf8();
     if (this_selection == last_selection_)
       return;
     last_selection_ = this_selection;
   }
 
   ui::Range range(ui::Range::InvalidRange());
   size_t location, length;
   if (webview()->caretOrSelectionRange(&location, &length)) {
     range.set_start(location);
     range.set_end(location + length);
   }
-  Send(new ViewHostMsg_SelectionChanged(routing_id_, last_selection_, range));
+
+  WebKit::WebPoint start, end;
+  webview()->selectionRange(start, end);
+
+  // Webkit gives an offset of 1 between start and end even if there is no
+  // selection. So we need to check against that.
+  // TODO(varunjain): remove this check once that is fixed.
+  gfx::Point p1, p2;
+  if (std::abs(start.x - end.x) > 1 || std::abs(start.y - end.y) > 1) {
+    gfx::Point scroll_offset = GetScrollOffset();
+    p1.SetPoint(start.x + scroll_offset.x(), start.y + scroll_offset.y());
+    p2.SetPoint(end.x + scroll_offset.x(), end.y + scroll_offset.y());
+  }
+  // TODO(varunjain): add other hooks for SelectionChanged.
+  Send(new ViewHostMsg_SelectionChanged(routing_id_, last_selection_, range,
+                                        p1, p2));
 #endif  // defined(OS_POSIX)
 }
 
 void RenderView::didExecuteCommand(const WebString& command_name) {
   const std::string& name = UTF16ToUTF8(command_name);
   if (StartsWithASCII(name, "Move", true) ||
       StartsWithASCII(name, "Insert", true) ||
       StartsWithASCII(name, "Delete", true))
     return;
   RenderThread::current()->Send(
@@ skipping 2884 matching lines @@
 }
 #endif
 
 void RenderView::OnContextMenuClosed(
     const webkit_glue::CustomContextMenuContext& custom_context) {
   if (custom_context.is_pepper_menu)
     pepper_delegate_.OnContextMenuClosed(custom_context);
   else
     context_menu_node_.reset();
 }