When receiving a key event on Windows, set host lock state to match client's

BUG=176436

Review-Url: https://codereview.chromium.org/2843213002
Cr-Commit-Position: refs/heads/master@{#468442}

remoting/host/input_injector_win.cc

@@ -199,6 +199,12 @@ class InputInjectorWin : public InputInjector {
     void HandleMouse(const MouseEvent& event);
     void HandleTouch(const TouchEvent& event);
 
+    // Check if the given scan code is caps lock or num lock.
+    bool IsLockKey(int scancode);
+
+    // Sets the keyboard lock states to those provided.
+    void SetLockStates(uint32_t states);
+
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
     std::unique_ptr<Clipboard> clipboard_;
@@ -348,6 +354,10 @@ void InputInjectorWin::Core::HandleKey(const KeyEvent& event) {
   if (scancode == ui::KeycodeConverter::InvalidNativeKeycode())
     return;
 
+  if (event.has_lock_states() && !IsLockKey(scancode)) {
+    SetLockStates(event.lock_states());
+  }
+
   uint32_t flags = KEYEVENTF_SCANCODE | (event.pressed() ? 0 : KEYEVENTF_KEYUP);
   SendKeyboardInput(flags, scancode);
 }
@@ -384,6 +394,38 @@ void InputInjectorWin::Core::HandleTouch(const TouchEvent& event) {
   touch_injector_->InjectTouchEvent(event);
 }
 
+bool InputInjectorWin::Core::IsLockKey(int scancode) {
+  UINT virtual_key = MapVirtualKey(scancode, MAPVK_VSC_TO_VK);
+  return virtual_key == VK_CAPITAL || virtual_key == VK_NUMLOCK;
+}
+
+void InputInjectorWin::Core::SetLockStates(uint32_t states) {
+  // Can't use SendKeyboardInput because we need to send virtual key codes, not
+  // scan codes.
+  INPUT input[2] = {};
+  input[0].type = INPUT_KEYBOARD;
+  input[1].type = INPUT_KEYBOARD;
+  input[1].ki.dwFlags = KEYEVENTF_KEYUP;
+
+  bool client_capslock_state =
+      (states & protocol::KeyEvent::LOCK_STATES_CAPSLOCK) != 0;
+  bool host_capslock_state = (GetKeyState(VK_CAPITAL) & 1) != 0;
+  if (client_capslock_state != host_capslock_state) {
+    input[0].ki.wVk = VK_CAPITAL;
+    input[1].ki.wVk = VK_CAPITAL;
+    SendInput(arraysize(input), input, sizeof(INPUT));
+  }
+
+  bool client_numlock_state =
+      (states & protocol::KeyEvent::LOCK_STATES_NUMLOCK) != 0;
+  bool host_numlock_state = (GetKeyState(VK_NUMLOCK) & 1) != 0;
+  if (client_numlock_state != host_numlock_state) {
+    input[0].ki.wVk = VK_NUMLOCK;
+    input[1].ki.wVk = VK_NUMLOCK;
+    SendInput(arraysize(input), input, sizeof(INPUT));
+  }
+}
+
 }  // namespace
 
 // static