Make mash register initial batch of accelerators in single shot.

ui/base/accelerators/accelerator_manager.h

Index: ui/base/accelerators/accelerator_manager.h
diff --git a/ui/base/accelerators/accelerator_manager.h b/ui/base/accelerators/accelerator_manager.h
index 9db9629fd8ecc8a9aabf7fa974fe15f1af2cdd75..42ab5d5a02bb377aaf023f2d2553723be27b1d2e 100644
--- a/ui/base/accelerators/accelerator_manager.h
+++ b/ui/base/accelerators/accelerator_manager.h
@@ -8,6 +8,7 @@
 #include <list>
 #include <map>
 #include <utility>
+#include <vector>
 
 #include "base/macros.h"
 #include "ui/base/accelerators/accelerator.h"
@@ -30,10 +31,10 @@ class UI_BASE_EXPORT AcceleratorManager {
   explicit AcceleratorManager(AcceleratorManagerDelegate* = nullptr);
   ~AcceleratorManager();
 
-  // Register a keyboard accelerator for the specified target. If multiple
+  // Register keyboard accelerators for the specified target. If multiple
   // targets are registered for an accelerator, a target registered later has
   // higher priority.
-  // |accelerator| is the accelerator to register.
+  // |accelerators| contain accelerators to register.
   // |priority| denotes the priority of the handler.
   // NOTE: In almost all cases, you should specify kNormalPriority for this
   // parameter. Setting it to kHighPriority prevents Chrome from sending the
@@ -47,7 +48,7 @@ class UI_BASE_EXPORT AcceleratorManager {
   // - the enter key
   // - any F key (F1, F2, F3 ...)
   // - any browser specific keys (as available on special keyboards)
-  void Register(const Accelerator& accelerator,
+  void Register(const std::vector<ui::Accelerator>& accelerators,
                 HandlerPriority priority,

[sky, 2017/01/27 19:11:14]

Each accelerator may want a different priority, so that Register should take a
vector of accelerator and priority pairs.

[mfomitchev, 2017/01/27 23:12:01]

We don't currently have a use case for registering a bunch of accelerators at
once with different priorities. Do you think we need to design for this now? 

[sky, 2017/01/28 00:09:15]

Given we don't have a need for it now, I'm ok with that is here.

One suggestion though. Given most sites only care about registering one
accelerator at a time, how about providing a function with the same name that is
inlined and calls the vector version?

[thanhph1, 2017/01/30 16:37:54]

I can't use the same name Register for inline function without extra
factorization because the call to Register({accelerator}, priority, target)
(also in unit tests) points the inline function instead of expected vector
version and this results to infinitive recursion calls. I use the name
RegisterAccelerator instead. If we keep the inline Register name, I need to
change from {accelerator} to std::vector<ui::Accelerator>(accelerator), which is
quite wordy. 

                 AcceleratorTarget* target);