Make most browser accelerators not repeat.

ui/base/accelerators/accelerator_manager.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 "ui/base/accelerators/accelerator_manager.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 
 namespace ui {
 
 AcceleratorManager::AcceleratorManager() {
 }
 
 AcceleratorManager::~AcceleratorManager() {
 }
 
 void AcceleratorManager::Register(const Accelerator& accelerator,
                                   HandlerPriority priority,
                                   AcceleratorTarget* target) {
   DCHECK(target);
   AcceleratorTargetList& targets = accelerators_[accelerator].second;
   DCHECK(std::find(targets.begin(), targets.end(), target) == targets.end())
       << "Registering the same target multiple times";
 
   // All priority accelerators go to the front of the line.
-  if (priority) {
+  if (priority == kHighPriority) {

[Daniel Erat, 2016/07/07 21:08:50]

this isn't exactly related but i saw the old code while i was investigating this
change and it freaked me out. :-P

     DCHECK(!accelerators_[accelerator].first)
-        << "Only one _priority_ handler can be registered";
+        << "Only one high-priority handler can be registered";
     targets.push_front(target);
     // Mark that we have a priority accelerator at the front.
     accelerators_[accelerator].first = true;
     return;
   }
 
   // We are registering a normal priority handler. If no priority accelerator
   // handler has been registered before us, just add the new handler to the
   // front. Otherwise, register it after the first (only) priority handler.
   if (!accelerators_[accelerator].first)
@@ skipping 68 matching lines @@
   // Check if we have a priority handler. If not, there's no more work needed.
   if (!map_iter->second.first)
     return false;
 
   // If the priority handler says it cannot handle the accelerator, we must not
   // count it as one.
   return map_iter->second.second.front()->CanHandleAccelerators();
 }
 
 }  // namespace ui