Add a skeleton of idle time spell checker

third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp

Index: third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
diff --git a/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..bdab6eb0cc4580bbe1216e5178f32e99cbb0f018
--- /dev/null
+++ b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
@@ -0,0 +1,159 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/spellcheck/IdleSpellCheckCallback.h"
+
+#include "core/dom/IdleRequestOptions.h"
+#include "core/editing/EditingUtilities.h"
+#include "core/editing/FrameSelection.h"
+#include "core/editing/VisibleSelection.h"
+#include "core/editing/VisibleUnits.h"
+#include "core/editing/commands/CompositeEditCommand.h"
+#include "core/editing/commands/UndoStep.h"
+#include "core/editing/iterators/BackwardsCharacterIterator.h"
+#include "core/editing/iterators/CharacterIterator.h"
+#include "core/editing/spellcheck/SpellCheckRequester.h"
+#include "core/editing/spellcheck/SpellChecker.h"
+#include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
+#include "core/html/TextControlElement.h"
+#include "core/layout/LayoutObject.h"
+#include "platform/RuntimeEnabledFeatures.h"
+#include "platform/tracing/TraceEvent.h"
+#include "wtf/CurrentTime.h"
+
+namespace blink {
+
+namespace {
+
+const int kColdModeTimerIntervalMS = 1000;
+const int kConsecutiveColdModeTimerIntervalMS = 200;
+const int kRequestTimeoutMS = 200;
+
+}  // namespace
+
+IdleSpellCheckCallback::~IdleSpellCheckCallback() {}
+
+DEFINE_TRACE(IdleSpellCheckCallback) {
+  visitor->trace(m_frame);
+  IdleRequestCallback::trace(visitor);
+}
+
+IdleSpellCheckCallback* IdleSpellCheckCallback::create(LocalFrame& frame) {
+  return new IdleSpellCheckCallback(frame);
+}
+
+IdleSpellCheckCallback::IdleSpellCheckCallback(LocalFrame& frame)
+    : m_state(State::kInactive),
+      m_frame(frame),
+      m_coldModeTimer(this, &IdleSpellCheckCallback::coldModeTimerFired) {}
+
+bool IdleSpellCheckCallback::isSpellCheckingEnabled() const {
+  // TODO(xiaochengh): decouple with SpellChecker.
+  return frame().spellChecker().isSpellCheckingEnabled();
+}
+
+void IdleSpellCheckCallback::requestInvocation() {
+  IdleRequestOptions options;
+  options.setTimeout(kRequestTimeoutMS);
+  frame().document()->requestIdleCallback(this, options);
+}
+
+void IdleSpellCheckCallback::deactivate() {
+  m_state = State::kInactive;
+  if (m_coldModeTimer.isActive())
+    m_coldModeTimer.stop();
+}
+
+void IdleSpellCheckCallback::setNeedsHotModeInvocation() {
+  if (!RuntimeEnabledFeatures::idleTimeSpellCheckingEnabled())
+    return;
+
+  if (!isSpellCheckingEnabled()) {
+    deactivate();
+    return;
+  }
+
+  if (m_state == State::kColdModeTimerStarted) {
+    DCHECK(m_coldModeTimer.isActive());
+    m_coldModeTimer.stop();
+  }
+
+  if (m_state != State::kColdModeRequested)
+    requestInvocation();
+  m_state = State::kHotModeRequested;
+}
+
+void IdleSpellCheckCallback::setNeedsColdModeInvocation() {
+  if (!RuntimeEnabledFeatures::idleTimeSpellCheckingEnabled())
+    return;
+
+  if (!isSpellCheckingEnabled()) {
+    deactivate();
+    return;
+  }
+
+  if (m_state != State::kInactive && m_state != State::kInHotModeInvocation &&
+      m_state != State::kInColdModeInvocation)
+    return;
+
+  DCHECK(!m_coldModeTimer.isActive());
+  int intervalMS = m_state == State::kInColdModeInvocation
+                       ? kConsecutiveColdModeTimerIntervalMS
+                       : kColdModeTimerIntervalMS;
+  m_coldModeTimer.startOneShot(intervalMS / 1000.0, BLINK_FROM_HERE);
+  m_state = State::kColdModeTimerStarted;
+}
+
+void IdleSpellCheckCallback::coldModeTimerFired(TimerBase*) {
+  DCHECK_EQ(State::kColdModeTimerStarted, m_state);
+
+  if (!isSpellCheckingEnabled()) {
+    deactivate();
+    return;
+  }
+
+  requestInvocation();
+  m_state = State::kColdModeRequested;
+}
+
+void IdleSpellCheckCallback::hotModeInvocation(IdleDeadline* deadline) {
+  // TODO(xiaochengh): Implementation.
+}
+
+void IdleSpellCheckCallback::coldModeInvocation(IdleDeadline* deadline) {
+  // TODO(xiaochengh): Implementation.
+}
+
+bool IdleSpellCheckCallback::coldModeFinishesFullDocument() const {
+  // TODO(xiaochengh): Implementation.
+  return true;
+}
+
+void IdleSpellCheckCallback::handleEvent(IdleDeadline* deadline) {
+  DCHECK(frame().document());
+  DCHECK(frame().document()->isActive());
+
+  if (!isSpellCheckingEnabled()) {
+    deactivate();
+    return;
+  }
+
+  if (m_state == State::kHotModeRequested) {
+    m_state = State::kInHotModeInvocation;
+    hotModeInvocation(deadline);
+    setNeedsColdModeInvocation();
+  } else if (m_state == State::kColdModeRequested) {
+    m_state = State::kInColdModeInvocation;
+    coldModeInvocation(deadline);
+    if (coldModeFinishesFullDocument())
+      m_state = State::kInactive;
+    else
+      setNeedsColdModeInvocation();
+  } else {
+    NOTREACHED();
+  }
+}
+
+}  // namespace blink