ime: Refactor request ID code.

Add a new struct representing a pending key event as we'll be adding
new data to the key event in a follow up patch.

Change-Id: I87040818e619236e2e514173ce66db64e66a1177
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816197
Commit-Queue: Darren Shen <shend@chromium.org>
Reviewed-by: Keith Lee <keithlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701939}

chrome/browser/extensions/api/input_ime/input_ime_api.cc

@@ -80,7 +80,7 @@ void ImeObserver::OnBlur(int context_id) {
 void ImeObserver::OnKeyEvent(
     const std::string& component_id,
     const InputMethodEngineBase::KeyboardEvent& event,
-    IMEEngineHandlerInterface::KeyEventDoneCallback key_data) {
+    IMEEngineHandlerInterface::KeyEventDoneCallback callback) {
   if (extension_id_.empty())
     return;
 
@@ -89,7 +89,7 @@ void ImeObserver::OnKeyEvent(
   if (!ShouldForwardKeyEvent()) {
     // Continue processing the key event so that the physical keyboard can
     // still work.
-    std::move(key_data).Run(false);
+    std::move(callback).Run(false);
     return;
   }
 
@@ -99,7 +99,7 @@ void ImeObserver::OnKeyEvent(
     return;
   const std::string request_id =
       event_router->GetEngineIfActive(extension_id_)
-          ->AddRequest(component_id, std::move(key_data));
+          ->AddPendingKeyEvent(component_id, std::move(callback));
 
   input_ime::KeyboardEvent key_data_value;
   key_data_value.type = input_ime::ParseKeyboardEventType(event.type);

chrome/browser/ui/input_method/input_method_engine_base.cc

@@ -151,7 +151,6 @@ InputMethodEngineBase::InputMethodEngineBase()
       context_id_(0),
       next_context_id_(1),
       profile_(nullptr),
-      next_request_id_(1),
       composition_changed_(false),
       text_(""),
       commit_text_changed_(false),
@@ -458,27 +457,38 @@ void InputMethodEngineBase::KeyEventHandled(const std::string& extension_id,
     composition_changed_ = false;
   }
 
-  auto request = request_map_.find(request_id);
-  if (request == request_map_.end()) {
+  const auto it = pending_key_events_.find(request_id);
+  if (it == pending_key_events_.end()) {
     LOG(ERROR) << "Request ID not found: " << request_id;
     return;
   }
 
-  std::move(request->second.second).Run(handled);
-  request_map_.erase(request);
+  std::move(it->second.callback).Run(handled);
+  pending_key_events_.erase(it);
 }
 
-std::string InputMethodEngineBase::AddRequest(
+std::string InputMethodEngineBase::AddPendingKeyEvent(
     const std::string& component_id,
-    ui::IMEEngineHandlerInterface::KeyEventDoneCallback key_data) {
+    ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback) {
   std::string request_id = base::NumberToString(next_request_id_);
   ++next_request_id_;
 
-  request_map_[request_id] = std::make_pair(component_id, std::move(key_data));
+  pending_key_events_.emplace(
+      request_id, PendingKeyEvent(component_id, std::move(callback)));
 
   return request_id;
 }
 
+InputMethodEngineBase::PendingKeyEvent::PendingKeyEvent(
+    const std::string& component_id,
+    ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback)
+    : component_id(component_id), callback(std::move(callback)) {}
+
+InputMethodEngineBase::PendingKeyEvent::PendingKeyEvent(
+    PendingKeyEvent&& other) = default;
+
+InputMethodEngineBase::PendingKeyEvent::~PendingKeyEvent() = default;
+
 void InputMethodEngineBase::DeleteSurroundingTextToInputContext(
     int offset,
     size_t number_of_chars) {

chrome/browser/ui/input_method/input_method_engine_base.h

@@ -197,10 +197,10 @@ class InputMethodEngineBase : virtual public ui::IMEEngineHandlerInterface {
                        const std::string& request_id,
                        bool handled);
 
-  // Adds unprocessed key event to |request_map_|.
-  std::string AddRequest(
+  // Returns the request ID for this key event.
+  std::string AddPendingKeyEvent(
       const std::string& component_id,
-      ui::IMEEngineHandlerInterface::KeyEventDoneCallback key_data);
+      ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback);
 
   int GetContextIdForTesting() const { return context_id_; }
 
@@ -210,6 +210,20 @@ class InputMethodEngineBase : virtual public ui::IMEEngineHandlerInterface {
   }
 
  protected:
+  struct PendingKeyEvent {
+    PendingKeyEvent(
+        const std::string& component_id,
+        ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback);
+    PendingKeyEvent(PendingKeyEvent&& other);
+    ~PendingKeyEvent();
+
+    std::string component_id;
+    ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(PendingKeyEvent);
+  };
+
   // Returns true if this IME is active, false if not.
   virtual bool IsActive() const = 0;
 
@@ -253,13 +267,8 @@ class InputMethodEngineBase : virtual public ui::IMEEngineHandlerInterface {
 
   Profile* profile_;
 
-  using RequestMap =
-      std::map<std::string,
-               std::pair<std::string,
-                         ui::IMEEngineHandlerInterface::KeyEventDoneCallback>>;
-
-  unsigned int next_request_id_;
-  RequestMap request_map_;
+  unsigned int next_request_id_ = 1;
+  std::map<std::string, PendingKeyEvent> pending_key_events_;
 
   // The composition text to be set from calling input.ime.setComposition API.
   ui::CompositionText composition_;