Add TRACE_EVENT markers to various keyboard functions

Adds the following under the "vk" trace marker group:
- ShowKeyboardInternal
- ShowKeyboardContainerWindow
- ShowKeyboardContainer
- KeyboardLayoutSetChildBounds
- OnTextInputStateChanged
- HideKeyboard
- ReloadKeyboardIfNeeded
- EnsureCaretInWorkArea
- MoveKeyboardToDisplay
- MoveKeyboardToTouchableDisplay
- MoveKeyboardToDisplayInternal
- LoadContents

BUG=725789

Review-Url: https://codereview.chromium.org/2923493002
Cr-Commit-Position: refs/heads/master@{#478539}

ash/virtual_keyboard_controller.cc

@@ -34,6 +34,7 @@ bool IsSmartVirtualKeyboardEnabled() {
 
 void MoveKeyboardToDisplayInternal(const int64_t display_id) {
   // Remove the keyboard from curent root window controller
+  TRACE_EVENT0("vk", "MoveKeyboardToDisplayInternal");
   Shell::Get()->keyboard_ui()->Hide();
   RootWindowController::ForWindow(
       keyboard::KeyboardController::GetInstance()->GetContainerWindow())
@@ -111,6 +112,8 @@ void VirtualKeyboardController::MoveKeyboardToDisplay(int64_t display_id) {
   DCHECK(keyboard::KeyboardController::GetInstance() != nullptr);
   DCHECK(display_id != display::kInvalidDisplayId);
 
+  TRACE_EVENT0("vk", "MoveKeyboardToDisplay");
+
   aura::Window* container =
       keyboard::KeyboardController::GetInstance()->GetContainerWindow();
   DCHECK(container != nullptr);
@@ -125,6 +128,8 @@ void VirtualKeyboardController::MoveKeyboardToDisplay(int64_t display_id) {
 void VirtualKeyboardController::MoveKeyboardToTouchableDisplay() {
   DCHECK(keyboard::KeyboardController::GetInstance() != nullptr);
 
+  TRACE_EVENT0("vk", "MoveKeyboardToTouchableDisplay");
+
   aura::Window* container =
       keyboard::KeyboardController::GetInstance()->GetContainerWindow();
   DCHECK(container != nullptr);

ui/keyboard/content/keyboard_ui_content.cc

@@ -240,6 +240,7 @@ void KeyboardUIContent::ReloadKeyboardIfNeeded() {
       // navigate to a keyboard in a different extension. This keeps the UX the
       // same as Android. Note we need to explicitly close current page as it
       // might try to resize keyboard window in javascript on a resize event.
+      TRACE_EVENT0("vk", "ReloadKeyboardIfNeeded");
       GetKeyboardWindow()->SetBounds(gfx::Rect());
       keyboard_contents_->ClosePage();
       keyboard_controller()->SetKeyboardMode(FULL_WIDTH);
@@ -325,6 +326,7 @@ const aura::Window* KeyboardUIContent::GetKeyboardRootWindow() const {
 
 void KeyboardUIContent::LoadContents(const GURL& url) {
   if (keyboard_contents_) {
+    TRACE_EVENT0("vk", "LoadContents");
     content::OpenURLParams params(url, content::Referrer(),
                                   WindowOpenDisposition::SINGLETON_TAB,
                                   ui::PAGE_TRANSITION_AUTO_TOPLEVEL, false);

ui/keyboard/keyboard_controller.cc

@@ -246,6 +246,8 @@ void KeyboardController::NotifyKeyboardBoundsChanging(
 }
 
 void KeyboardController::HideKeyboard(HideReason reason) {
+  TRACE_EVENT0("vk", "HideKeyboard");
+
   keyboard_visible_ = false;
   ToggleTouchEventLogging(true);
 
@@ -377,6 +379,8 @@ void KeyboardController::OnTextInputStateChanged(
   if (!container_.get())
     return;
 
+  TRACE_EVENT0("vk", "OnTextInputStateChanged");
+
   ui::TextInputType type =
       client ? client->GetTextInputType() : ui::TEXT_INPUT_TYPE_NONE;
 
@@ -423,6 +427,8 @@ void KeyboardController::ShowKeyboardInternal(int64_t display_id) {
   // |Shell::CreateKeyboard| is called.
   DCHECK(container_.get());
 
+  TRACE_EVENT0("vk", "ShowKeyboardInternal");
+
   if (container_->children().empty()) {
     keyboard::MarkKeyboardLoadStarted();
     aura::Window* keyboard = ui_->GetKeyboardWindow();

ui/keyboard/keyboard_layout_manager.cc

@@ -44,6 +44,8 @@ void KeyboardLayoutManager::SetChildBounds(aura::Window* child,
                                            const gfx::Rect& requested_bounds) {
   DCHECK(child == keyboard_);
 
+  TRACE_EVENT0("vk", "KeyboardLayoutSetChildBounds");
+
   // Request to change the bounds of child window (AKA the virtual keyboard
   // window) should change the container window first. Then the child window is
   // resized and covers the container window. Note the child's bound is only set

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()