Fix conflicts between accelerator keys and HTML DOM accesskeys....

chrome/browser/views/tab_contents/tab_contents_view_win.cc

 // Copyright (c) 2006-2008 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/views/tab_contents/tab_contents_view_win.h"
 
 #include <windows.h>
 
 #include "app/gfx/canvas_paint.h"
 #include "app/os_exchange_data.h"
@@ skipping 333 matching lines @@
     views::FocusManager* focus_manager =
         views::FocusManager::GetFocusManagerForNativeView(GetNativeView());
 
     // We may not have a focus manager if the tab has been switched before this
     // message arrived.
     if (focus_manager)
       focus_manager->AdvanceFocus(reverse);
   }
 }
 
-void TabContentsViewWin::HandleKeyboardEvent(
+bool TabContentsViewWin::HandleKeyboardEvent(
     const NativeWebKeyboardEvent& event) {
   // Previous calls to TranslateMessage can generate CHAR events as well as
   // RAW_KEY_DOWN events, even if the latter triggered an accelerator.  In these
   // cases, we discard the CHAR events.
   if (event.type == WebInputEvent::Char && ignore_next_char_event_) {
     ignore_next_char_event_ = false;
-    return;
+    return true;
   }
   ignore_next_char_event_ = false;
 
   // The renderer returned a keyboard event it did not process. This may be
   // a keyboard shortcut that we have to process.
   if (event.type == WebInputEvent::RawKeyDown) {
     views::FocusManager* focus_manager =
         views::FocusManager::GetFocusManagerForNativeView(GetNativeView());
     // We may not have a focus_manager at this point (if the tab has been
     // switched by the time this message returned).
     if (focus_manager) {
       views::Accelerator accelerator(
           win_util::WinToKeyboardCode(event.windowsKeyCode),
           (event.modifiers & WebInputEvent::ShiftKey) ==
               WebInputEvent::ShiftKey,
           (event.modifiers & WebInputEvent::ControlKey) ==
               WebInputEvent::ControlKey,
           (event.modifiers & WebInputEvent::AltKey) ==
               WebInputEvent::AltKey);
 
       // This is tricky: we want to set ignore_next_char_event_ if
       // ProcessAccelerator returns true. But ProcessAccelerator might delete
       // |this| if the accelerator is a "close tab" one. So we speculatively
       // set the flag and fix it if no event was handled.
       ignore_next_char_event_ = true;
       if (focus_manager->ProcessAccelerator(accelerator)) {
         // DANGER: |this| could be deleted now!
-        return;
+        return true;
       } else {
         // ProcessAccelerator didn't handle the accelerator, so we know both
         // that |this| is still valid, and that we didn't want to set the flag.
         ignore_next_char_event_ = false;
       }
     }
   }
 
   if (tab_contents()->delegate() &&
       tab_contents()->delegate()->HandleKeyboardEvent(event)) {
-    return;
+    return true;
   }
 
   // Any unhandled keyboard/character messages should be defproced.
   // This allows stuff like Alt+F4, etc to work correctly.
-  DefWindowProc(event.os_event.hwnd,
-                event.os_event.message,
-                event.os_event.wParam,
-                event.os_event.lParam);
+  DefWindowProc(event.os_event.hwnd, event.os_event.message,
+                event.os_event.wParam, event.os_event.lParam);
+
+  // DefWindowProc() always returns 0, which means it handled the event.
+  // But actually DefWindowProc() will only handle very few system key strokes,
+  // such as F10, Alt+Tab, Alt+F4, Alt+Esc, etc.
+  // So returning false here is just ok for most cases.
+  // Reference: http://msdn.microsoft.com/en-us/library/ms646267(VS.85).aspx
+  return false;
 }
 
 views::FocusManager* TabContentsViewWin::GetFocusManager() {
   views::FocusManager* focus_manager = WidgetWin::GetFocusManager();
   if (focus_manager) {
     // If focus_manager_ is non NULL, it means we have been reparented, in which
     // case its value may not be valid anymore.
     focus_manager_ = NULL;
     return focus_manager;
   }
@@ skipping 227 matching lines @@
   }
   return false;
 }
 
 void TabContentsViewWin::WheelZoom(int distance) {
   if (tab_contents()->delegate()) {
     bool zoom_in = distance > 0;
     tab_contents()->delegate()->ContentsZoomChange(zoom_in);
   }
 }