Refactoring the ownership of ui::InputMethod.

ui/aura/window_tree_host.cc

Index: ui/aura/window_tree_host.cc
diff --git a/ui/aura/window_tree_host.cc b/ui/aura/window_tree_host.cc
index e60208be8c19b09974210da56efa2e38134f23d5..433811ee339e2c31b380794b17c296b0e7503d9e 100644
--- a/ui/aura/window_tree_host.cc
+++ b/ui/aura/window_tree_host.cc
@@ -13,6 +13,8 @@
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_targeter.h"
 #include "ui/aura/window_tree_host_observer.h"
+#include "ui/base/ime/input_method.h"
+#include "ui/base/ime/input_method_factory.h"
 #include "ui/base/view_prop.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
@@ -41,6 +43,10 @@ float GetDeviceScaleFactorFromDisplay(Window* window) {
 
 WindowTreeHost::~WindowTreeHost() {
   DCHECK(!compositor_) << "compositor must be destroyed before root window";
+  if (owned_input_method_) {
+    delete input_method_;
+    input_method_ = nullptr;
+  }
 }
 
 #if defined(OS_ANDROID)
@@ -50,7 +56,7 @@ WindowTreeHost* WindowTreeHost::Create(const gfx::Rect& bounds) {
   // adding the CHECK.
   // TODO(sky): decide if we want a factory.
   CHECK(false);
-  return NULL;
+  return nullptr;
 }
 #endif
 
@@ -176,8 +182,27 @@ void WindowTreeHost::MoveCursorToHostLocation(const gfx::Point& host_location) {
 // WindowTreeHost, protected:
 
 WindowTreeHost::WindowTreeHost()
-    : window_(new Window(NULL)),
-      last_cursor_(ui::kCursorNull) {
+    : window_(new Window(nullptr)),
+      last_cursor_(ui::kCursorNull),
+      input_method_(nullptr),
+      owned_input_method_(false) {
+}
+
+ui::InputMethod* WindowTreeHost::GetInputMethod() {

[sky, 2015/06/04 13:40:28]

Make order match header.

[Shu Chen, 2015/06/04 15:59:25]

Done.

+  if (!input_method_) {
+    input_method_ =
+        ui::CreateInputMethod(this, GetAcceleratedWidget()).release();
+    // Makes sure the input method is focused by default when created.

[sky, 2015/06/04 13:40:28]

This doesn't make sense to me. Why does the input_method_ need an initial focus.

[Shu Chen, 2015/06/04 15:59:25]

InputMethod::OnFocus() should be called when a native root window
(WindowTreeHost) is activated/focused.
However, for Ash, WindowTreeHost doesn't have the activation/focus state, and
WindowTreeHost::OnHostActivated() never gets called.
So here to make InputMethod by default focused is to make Ash work.
I've added this into the comment.

[sky, 2015/06/04 19:42:52]

This code effects desktop too though. Is that ok? You should add a more
descriptive comment too.

[Shu Chen, 2015/06/05 00:52:18]

It is ok, because this behavior remains no change as original:
https://code.google.com/p/chromium/codesearch#chromium/src/ui/wm/core/input_m...

I can move this OnFocus call to DisplayController so it will be Ash only, but it
would be safer to have a separated CL to do that for easier rollback on
regressions.

+    input_method_->OnFocus();
+    owned_input_method_ = true;
+  }
+  return input_method_;
+};
+
+void WindowTreeHost::SetInputMethod(ui::InputMethod* input_method) {
+  DCHECK(!input_method_);
+  input_method_ = input_method;
+  owned_input_method_ = false;
 }
 
 void WindowTreeHost::DestroyCompositor() {
@@ -186,7 +211,7 @@ void WindowTreeHost::DestroyCompositor() {
 
 void WindowTreeHost::DestroyDispatcher() {
   delete window_;
-  window_ = NULL;
+  window_ = nullptr;
   dispatcher_.reset();
 
   // TODO(beng): this comment is no longer quite valid since this function
@@ -259,6 +284,30 @@ void WindowTreeHost::OnHostLostWindowCapture() {
     capture_window->ReleaseCapture();
 }
 
+bool WindowTreeHost::DispatchKeyEventPostIME(const ui::KeyEvent& event) {
+  ui::KeyEvent copied_event(event);
+  ui::EventDispatchDetails details =
+      event_processor()->OnEventFromSource(&copied_event);
+  DCHECK(!details.dispatcher_destroyed);
+  return copied_event.handled();
+}
+
+ui::EventProcessor* WindowTreeHost::GetEventProcessor() {
+  return event_processor();
+}
+
+ui::EventDispatchDetails WindowTreeHost::DeliverEventToProcessor(
+    ui::Event* event) {
+  if (event->IsKeyEvent()) {
+    if (GetInputMethod()->DispatchKeyEvent(
+            *static_cast<ui::KeyEvent*>(event))) {
+      event->StopPropagation();
+      return ui::EventDispatchDetails();
+    }
+  }
+  return ui::EventSource::DeliverEventToProcessor(event);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHost, private: