Grab mouse capture in the WM_POINTERDOWN message handler in the omnibox.

chrome/browser/ui/views/omnibox/omnibox_view_win.cc

 // 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.
 
 #include "chrome/browser/ui/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
@@ skipping 1431 matching lines @@
       break;
     default:
       break;
   }
   return DefWindowProc(message, wparam, lparam);
 }
 
 LRESULT OmniboxViewWin::OnPointerDown(UINT message,
                                       WPARAM wparam,
                                       LPARAM lparam) {
-  if (!model()->has_focus())
+  if (!model()->has_focus()) {
     SetFocus();
+    // The WM_POINTERDOWN message is received in Windows 8 mode when we touch
+    // the window/click on it. There appears to be a bug in Windows 8 where in
+    // the generated WM_LBUTTONDOWN/UP messages go to the window which
+    // previously had focus. We set capture here to ensure that the generated
+    // mouse messages come to us.
+    SetCapture();
+  }
 
   if (IS_POINTER_FIRSTBUTTON_WPARAM(wparam)) {
     TrackMousePosition(kLeft, CPoint(GET_X_LPARAM(lparam),
                                      GET_Y_LPARAM(lparam)));
   }
-
   SetMsgHandled(false);
-
   return 0;
 }
 
 LRESULT OmniboxViewWin::OnPointerUp(UINT message, WPARAM wparam,
                                     LPARAM lparam) {
   SetMsgHandled(false);
-
+  if (m_hWnd == GetCapture())

[sky, 2012/10/11 21:28:12]

Is this invoked as you release each finger? If so, do we only want to do this if
there are no touch devices down?

[ananta, 2012/10/11 21:59:10]

The only way to get info about touch points is to register the window for touch.
That might bring about changes in behavior due to differences in some messages.

I added a check to only set capture if the first button is down and to release
it when it is up.

+    ReleaseCapture();
   return 0;
 }
 
 void OmniboxViewWin::OnKeyDown(TCHAR key,
                                UINT repeat_count,
                                UINT flags) {
   delete_at_end_pressed_ = false;
 
   if (OnKeyDownAllModes(key, repeat_count, flags))
     return;
@@ skipping 1200 matching lines @@
   return (rect.left - client_rect.left) + (client_rect.right - rect.right);
 }
 
 int OmniboxViewWin::WidthNeededToDisplay(const string16& text) const {
   // Use font_.GetStringWidth() instead of
   // PosFromChar(location_entry_->GetTextLength()) because PosFromChar() is
   // apparently buggy. In both LTR UI and RTL UI with left-to-right layout,
   // PosFromChar(i) might return 0 when i is greater than 1.
   return font_.GetStringWidth(text) + GetHorizontalMargin();
 }