Add TRACE_EVENT markers to various keyboard functions

ui/keyboard/keyboard_ui.cc

Index: ui/keyboard/keyboard_ui.cc
diff --git a/ui/keyboard/keyboard_ui.cc b/ui/keyboard/keyboard_ui.cc
index 4770f6fc9f33c7a9d3207154b8c566c05ee477ca..a0e65ac758cd883a6b858e35e8911e13f7d0794f 100644
--- a/ui/keyboard/keyboard_ui.cc
+++ b/ui/keyboard/keyboard_ui.cc
@@ -18,8 +18,14 @@ KeyboardUI::~KeyboardUI() {}
 
 void KeyboardUI::ShowKeyboardContainer(aura::Window* container) {
   if (HasKeyboardWindow()) {
-    GetKeyboardWindow()->Show();
-    container->Show();
+    {
+      TRACE_EVENT0("vk", "ShowKeyboardContainerWindow");
+      GetKeyboardWindow()->Show();
+    }
+    {
+      TRACE_EVENT0("vk", "ShowKeyboardContainer");
+      container->Show();
+    }
   }
 }
 
@@ -34,6 +40,8 @@ void KeyboardUI::EnsureCaretInWorkArea() {
   if (!GetInputMethod())
     return;
 
+  TRACE_EVENT0("vk", "EnsureCaretInWorkArea");
+
   const aura::Window* keyboard_window = GetKeyboardWindow();
   const gfx::Rect keyboard_bounds_in_screen =
       keyboard_window->IsVisible() ? keyboard_window->GetBoundsInScreen()