[linux] Adds raw key events plugin.

library/linux/src/embedder.cc

@@ -26,6 +26,7 @@
 
 #include <flutter_embedder.h>
 
+#include "library/linux/src/internal/key_event_plugin.h"
 #include "library/linux/src/internal/keyboard_hook_handler.h"
 #include "library/linux/src/internal/plugin_handler.h"
 #include "library/linux/src/internal/text_input_plugin.h"
@@ -275,13 +276,17 @@ GLFWwindow *CreateFlutterWindow(size_t initial_width, size_t initial_height,
   FlutterEmbedderState *state = new FlutterEmbedderState();
   state->plugin_handler = std::make_unique<PluginHandler>(engine);
   state->engine = engine;
+
+  auto key_event_plugin = std::make_unique<KeyEventPlugin>();
+  state->keyboard_hook_handlers.push_back(key_event_plugin.get());
   auto input_plugin = std::make_unique<TextInputPlugin>();
   state->keyboard_hook_handlers.push_back(input_plugin.get());
-
+  
   glfwSetWindowUserPointer(window, state);
 
+  AddPlugin(window, std::move(key_event_plugin));
   AddPlugin(window, std::move(input_plugin));
-
+  
   int width, height;
   glfwGetWindowSize(window, &width, &height);
   GLFWwindowSizeCallback(window, width, height);

library/linux/src/internal/key_event_plugin.cc

@@ -0,0 +1,60 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include "library/linux/src/internal/key_event_plugin.h"
+#include <flutter_embedder.h>
+#include <iostream>
+
+static constexpr char kChannelName[] = "flutter/keyevent";
+
+static constexpr char kKeyCodeKey[] = "keyCode";
+static constexpr char kKeyMapKey[] = "keymap";
+static constexpr char kTypeKey[] = "type";
+
+static constexpr char kAndroidKeyMap[] = "android";
+static constexpr char kKeyUp[] = "keyup";
+static constexpr char kKeyDown[] = "keydown";
+// TODO: This event is not supported by Flutter. Add once it's implemented.
+static constexpr char kRepeat[] = "repeat";
+
+namespace flutter_desktop_embedding {
+KeyEventPlugin::KeyEventPlugin() : JsonPlugin(kChannelName, false) {}
+
+KeyEventPlugin::~KeyEventPlugin() {}
+
+void KeyEventPlugin::CharHook(GLFWwindow *window, unsigned int code_point) {}
+
+void KeyEventPlugin::KeyboardHook(GLFWwindow *window, int key, int scancode,
+                                  int action, int mods) {
+  Json::Value args;
+  args[kKeyCodeKey] = key;
+  args[kKeyMapKey] = kAndroidKeyMap;
+  switch (action) {
+    case GLFW_PRESS:
+      args[kTypeKey] = kKeyDown;
+      break;
+    case GLFW_RELEASE:
+      args[kTypeKey] = kKeyUp;
+      break;
+    default:
+      break;
+  }
+  /// Messages to flutter/keyevent channels have no method name.
+  InvokeMethod("", args);
+}
+
+void KeyEventPlugin::HandleJsonMethodCall(
+    const JsonMethodCall &method_call, std::unique_ptr<MethodResult> result) {
+        // There are no methods invoked from Flutter on this channel.
+    }
+}  // namespace flutter_desktop_embedding

library/linux/src/internal/key_event_plugin.h

@@ -0,0 +1,39 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef LIBRARY_LINUX_SRC_INTERNAL_KEY_EVENT_PLUGIN_H_
+#define LIBRARY_LINUX_SRC_INTERNAL_kEY_EVENT_PLUGIN_H_
+
+#include "library/linux/include/flutter_desktop_embedding/json_plugin.h"
+#include "library/linux/src/internal/keyboard_hook_handler.h"
+
+namespace flutter_desktop_embedding {
+class KeyEventPlugin : public KeyboardHookHandler, public JsonPlugin {
+ public:
+  KeyEventPlugin();
+  virtual ~KeyEventPlugin();
+
+  // Plugin.
+  void HandleJsonMethodCall(const JsonMethodCall &method_call,
+                            std::unique_ptr<MethodResult> result) override;
+
+  // KeyboardHookHandler.
+  void KeyboardHook(GLFWwindow *window, int key, int scancode, int action,
+                    int mods) override;
+
+  // KeyboardHookHandler.
+  void CharHook(GLFWwindow *window, unsigned int code_point) override;
+};
+}  // namespace flutter_desktop_embedding
+
+#endif  // LIBRARY_LINUX_SRC_INTERNAL_KEY_EVENT_PLUGIN_H_

library/linux/src/json_method_codec.cc

@@ -49,6 +49,10 @@ std::unique_ptr<MethodCall> JsonMethodCodec::DecodeMethodCallInternal(
 std::unique_ptr<std::vector<uint8_t>> JsonMethodCodec::EncodeMethodCallInternal(
     const MethodCall &method_call) const {
   Json::Value message(Json::objectValue);
+  if (method_call.method_name().empty()) {
+    return EncodeJsonObject(
+        *static_cast<const Json::Value *>(method_call.arguments()));
+  }
   message[kMessageMethodKey] = method_call.method_name();
   message[kMessageArgumentsKey] =
       *static_cast<const Json::Value *>(method_call.arguments());