Fix large cursors not to trigger MouseLock

BUG=429322

Review URL: https://codereview.chromium.org/693893005

Cr-Commit-Position: refs/heads/master@{#302493}

remoting/client/plugin/chromoting_instance.cc

@@ -629,7 +629,7 @@ void ChromotingInstance::SetCursorShape(
     dictionary.Set(pp::Var("hotspotY"), cursor_hotspot.y());
     dictionary.Set(pp::Var("data"), array_buffer);
     PostChromotingMessage("setCursorShape", dictionary);
-    input_handler_.SetMouseCursor(nullptr, cursor_hotspot);
+    input_handler_.HideMouseCursor();
   } else {
     if (delegate_large_cursors_) {
       pp::VarDictionary dictionary;

remoting/client/plugin/pepper_input_handler.cc

@@ -218,6 +218,11 @@ void PepperInputHandler::SetMouseCursor(scoped_ptr<pp::ImageData> image,
   }
 }
 
+void PepperInputHandler::HideMouseCursor() {
+  cursor_image_.reset();
+  pp::MouseCursor::SetCursor(instance_, PP_MOUSECURSOR_TYPE_NONE);
+}
+
 void PepperInputHandler::MouseLockLost() {
   DCHECK(mouse_lock_state_ == MouseLockOn ||
          mouse_lock_state_ == MouseLockCancelling);

remoting/client/plugin/pepper_input_handler.h

@@ -43,11 +43,15 @@ class PepperInputHandler : public pp::MouseLock {
   // Called when the plugin receives or loses focus.
   void DidChangeFocus(bool has_focus);
 
-  // Sets the mouse cursor image. Passing NULL image will lock the mouse if
-  // mouse lock is enabled.
+  // Sets the mouse cursor image. Passing NULL |image| will cause the cursor to
+  // be hidden.
+  // Passing NULL |image| will also cause mouse-lock to be entered, if allowed.
   void SetMouseCursor(scoped_ptr<pp::ImageData> image,
                       const pp::Point& hotspot);
 
+  // Hides the mousr cursor without triggering mouse-lock.
+  void HideMouseCursor();
+
   // Enable or disable sending mouse input when the plugin does not have input
   // focus.
   void set_send_mouse_input_when_unfocused(bool send) {