Revert of Fix breaking change in It2me Host on Ozone (patchset #2 id:20001 of...

Revert of Fix breaking change in It2me Host on Ozone (patchset #2 id:20001 of https://codereview.chromium.org/931393003/)

Reason for revert:
does not compile

Original issue's description:
> Fix breaking change in It2me Host on Ozone
>
> Due to a recent threading changes, the Ozone SystemInputInjector must be
> created on the UI thread.
>
> This CL moves the creation of the input injector and input controller on
> to the browser UI thread.
>
> BUG=458314
>
> Committed: https://crrev.com/9c59eedd7720845a5bc93b6dbc72639305c52ea7
> Cr-Commit-Position: refs/heads/master@{#316883}

TBR=sergeyu@chromium.org,kelvinp@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=458314

Review URL: https://codereview.chromium.org/932233002

Cr-Commit-Position: refs/heads/master@{#316898}

remoting/host/input_injector_chromeos.cc

@@ -74,7 +74,13 @@ class InputInjectorChromeos::Core {
   DISALLOW_COPY_AND_ASSIGN(Core);
 };
 
-InputInjectorChromeos::Core::Core() : saved_auto_repeat_enabled_(false) {
+InputInjectorChromeos::Core::Core(scoped_ptr<ui::SystemInputInjector> delegate,
+                                  ui::InputController* input_controller)
+    : delegate_(delegate.Pass()),
+      input_controller_(input_controller),
+      saved_auto_repeat_enabled_(false) {
+  DCHECK(delegate_);
+  DCHECK(input_controller_);
 }
 
 void InputInjectorChromeos::Core::InjectClipboardEvent(
@@ -150,13 +156,6 @@ void InputInjectorChromeos::Core::InjectMouseEvent(const MouseEvent& event) {
 
 void InputInjectorChromeos::Core::Start(
     scoped_ptr<protocol::ClipboardStub> client_clipboard) {
-  ui::OzonePlatform* ozone_platform = ui::OzonePlatform::GetInstance();
-  delegate_ = ozone_platform->CreateSystemInputInjector();
-  DCHECK(delegate_);
-  input_controller_ = ozone_platform->GetInputController();
-  DCHECK(input_controller_);
-
-  // Implemented by remoting::ClipboardAura.
   clipboard_ = Clipboard::Create();
   clipboard_->Start(client_clipboard.Pass());
   point_transformer_.reset(new PointTransformer());
@@ -165,7 +164,9 @@ void InputInjectorChromeos::Core::Start(
 InputInjectorChromeos::InputInjectorChromeos(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
     : input_task_runner_(task_runner) {
-  core_.reset(new Core());
+  ui::OzonePlatform* ozone_platform = ui::OzonePlatform::GetInstance();
+  core_.reset(new Core(ozone_platform->CreateSystemInputInjector(),
+                       ozone_platform->GetInputController()));
 }
 
 InputInjectorChromeos::~InputInjectorChromeos() {