Revert 263647 "Revert 263644 "[DevTools] Touch emulation in cont..."

Static initializers issue was fixed in r263789.

> Revert 263644 "[DevTools] Touch emulation in content."
> 
> Reason for revert: broke
> http://build.chromium.org/p/chromium/builders/Linux%20x64/builds/63653/
> by introducing two new static-initializers into the chrome binary:
> # velocity_tracker.cc ui::(anonymous namespace)::LeastSquaresVelocityTrackerStrategy::HORIZON
> # velocity_tracker.cc ui::(anonymous namespace)::ASSUME_POINTER_STOPPED_TIME
> 
> > [DevTools] Touch emulation in content.
> > 
> > When renderer requests touch emulation using mouse, host creates
> > a TouchEmulator object and passes mouse, mouse wheel and keyboard events
> > to emulator before sending them to renderer.
> > 
> > Emulator completely blocks mouse-related events, and instead generates
> > touch events. Those touch events are handled over to gesture provider
> > after being acked by renderer. Resulting gestures are sent to the renderer.
> > 
> > When shift is pressed, scroll gestures are converted to pinch gestures, so
> > user can scale the page. This is required because multitouch is not yet
> > supported by emulator.
> > 
> > BUG=337142
> > 
> > Review URL: https://codereview.chromium.org/138163016
> 
> TBR=dgozman@chromium.org
> 
> Review URL: https://codereview.chromium.org/237353003

TBR=fischman@chromium.org

Review URL: https://codereview.chromium.org/236063014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263806 0039d316-1c4b-4281-b951-d872f2087c98

16 files changed, 1138 insertions, 13 deletions

diff --git a/content/browser/renderer_host/input/touch_emulator.cc b/content/browser/renderer_host/input/touch_emulator.cc
new file mode 100644
index 0000000..b0d43e2
--- /dev/null
+++ b/content/browser/renderer_host/input/touch_emulator.cc
@@ -0,0 +1,371 @@
+// Copyright 2014 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 "content/browser/renderer_host/input/touch_emulator.h"
+
+#include "content/browser/renderer_host/input/motion_event_web.h"
+#include "content/browser/renderer_host/input/web_input_event_util.h"
+#include "content/public/common/content_client.h"
+#include "content/public/common/content_switches.h"
+#include "grit/content_resources.h"
+#include "third_party/WebKit/public/platform/WebCursorInfo.h"
+#include "ui/events/gesture_detection/gesture_config_helper.h"
+#include "ui/gfx/image/image.h"
+
+using blink::WebGestureEvent;
+using blink::WebInputEvent;
+using blink::WebKeyboardEvent;
+using blink::WebMouseEvent;
+using blink::WebMouseWheelEvent;
+using blink::WebTouchEvent;
+using blink::WebTouchPoint;
+
+namespace content {
+
+namespace {
+
+ui::GestureProvider::Config GetGestureProviderConfig() {
+  // TODO(dgozman): Use different configs to emulate mobile/desktop as
+  // requested by renderer.
+  ui::GestureProvider::Config config = ui::DefaultGestureProviderConfig();
+  config.gesture_begin_end_types_enabled = false;
+  return config;
+}
+
+// Time between two consecutive mouse moves, during which second mouse move
+// is not converted to touch.
+const double kMouseMoveDropIntervalSeconds = 5.f / 1000;
+
+} // namespace
+
+TouchEmulator::TouchEmulator(TouchEmulatorClient* client)
+    : client_(client),
+      gesture_provider_(GetGestureProviderConfig(), this),
+      enabled_(false),
+      allow_pinch_(false) {
+  DCHECK(client_);
+  ResetState();
+
+  InitCursorFromResource(&touch_cursor_, IDR_DEVTOOLS_TOUCH_CURSOR_ICON);
+  InitCursorFromResource(&pinch_cursor_, IDR_DEVTOOLS_PINCH_CURSOR_ICON);
+
+  WebCursor::CursorInfo cursor_info;
+  cursor_info.type = blink::WebCursorInfo::TypePointer;
+  pointer_cursor_.InitFromCursorInfo(cursor_info);
+
+  // TODO(dgozman): Use synthetic secondary touch to support multi-touch.
+  gesture_provider_.SetMultiTouchSupportEnabled(false);
+  // TODO(dgozman): Enable double tap if requested by the renderer.
+  // TODO(dgozman): Don't break double-tap-based pinch with shift handling.
+  gesture_provider_.SetDoubleTapSupportForPlatformEnabled(false);
+}
+
+TouchEmulator::~TouchEmulator() {
+  // We cannot cleanup properly in destructor, as we need roundtrip to the
+  // renderer for ack. Instead, the owner should call Disable, and only
+  // destroy this object when renderer is dead.
+}
+
+void TouchEmulator::ResetState() {
+  last_mouse_event_was_move_ = false;
+  last_mouse_move_timestamp_ = 0;
+  mouse_pressed_ = false;
+  shift_pressed_ = false;
+  touch_active_ = false;
+  suppress_next_fling_cancel_ = false;
+  pinch_scale_ = 1.f;
+  pinch_gesture_active_ = false;
+}
+
+void TouchEmulator::Enable(bool allow_pinch) {
+  if (!enabled_) {
+    enabled_ = true;
+    ResetState();
+  }
+  allow_pinch_ = allow_pinch;
+  UpdateCursor();
+}
+
+void TouchEmulator::Disable() {
+  if (!enabled_)
+    return;
+
+  enabled_ = false;
+  UpdateCursor();
+  CancelTouch();
+}
+
+void TouchEmulator::InitCursorFromResource(WebCursor* cursor, int resource_id) {
+  gfx::Image& cursor_image =
+      content::GetContentClient()->GetNativeImageNamed(resource_id);
+  WebCursor::CursorInfo cursor_info;
+  cursor_info.type = blink::WebCursorInfo::TypeCustom;
+  // TODO(dgozman): Add HiDPI cursors.
+  cursor_info.image_scale_factor = 1.f;
+  cursor_info.custom_image = cursor_image.AsBitmap();
+  cursor_info.hotspot =
+      gfx::Point(cursor_image.Width() / 2, cursor_image.Height() / 2);
+#if defined(OS_WIN)
+  cursor_info.external_handle = 0;
+#endif
+
+  cursor->InitFromCursorInfo(cursor_info);
+}
+
+bool TouchEmulator::HandleMouseEvent(const WebMouseEvent& mouse_event) {
+  if (!enabled_)
+    return false;
+
+  if (mouse_event.button != WebMouseEvent::ButtonLeft)
+    return true;
+
+  if (mouse_event.type == WebInputEvent::MouseMove) {
+    if (last_mouse_event_was_move_ &&
+        mouse_event.timeStampSeconds < last_mouse_move_timestamp_ +
+            kMouseMoveDropIntervalSeconds)
+      return true;
+
+    last_mouse_event_was_move_ = true;
+    last_mouse_move_timestamp_ = mouse_event.timeStampSeconds;
+  } else {
+    last_mouse_event_was_move_ = false;
+  }
+
+  if (mouse_event.type == WebInputEvent::MouseDown)
+    mouse_pressed_ = true;
+  else if (mouse_event.type == WebInputEvent::MouseUp)
+    mouse_pressed_ = false;
+
+  UpdateShiftPressed((mouse_event.modifiers & WebInputEvent::ShiftKey) != 0);
+
+  if (FillTouchEventAndPoint(mouse_event) &&
+      gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_))) {
+    client_->ForwardTouchEvent(touch_event_);
+  }
+
+  // Do not pass mouse events to the renderer.
+  return true;
+}
+
+bool TouchEmulator::HandleMouseWheelEvent(const WebMouseWheelEvent& event) {
+  if (!enabled_)
+    return false;
+
+  // No mouse wheel events for the renderer.
+  return true;
+}
+
+bool TouchEmulator::HandleKeyboardEvent(const WebKeyboardEvent& event) {
+  if (!enabled_)
+    return false;
+
+  if (!UpdateShiftPressed((event.modifiers & WebInputEvent::ShiftKey) != 0))
+    return false;
+
+  if (!mouse_pressed_)
+    return false;
+
+  // Note: The necessary pinch events will be lazily inserted by
+  // |OnGestureEvent| depending on the state of |shift_pressed_|, using the
+  // scroll stream as the event driver.
+  if (shift_pressed_) {
+    // TODO(dgozman): Add secondary touch point and set anchor.
+  } else {
+    // TODO(dgozman): Remove secondary touch point and anchor.
+  }
+
+  // Never block keyboard events.
+  return false;
+}
+
+bool TouchEmulator::HandleTouchEventAck(InputEventAckState ack_result) {
+  const bool event_consumed = ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
+  gesture_provider_.OnTouchEventAck(event_consumed);
+  // TODO(dgozman): Disable emulation when real touch events are available.
+  return true;
+}
+
+void TouchEmulator::OnGestureEvent(const ui::GestureEventData& gesture) {
+  WebGestureEvent gesture_event =
+      CreateWebGestureEventFromGestureEventData(gesture);
+
+  switch (gesture_event.type) {
+    case WebInputEvent::GestureScrollBegin:
+      client_->ForwardGestureEvent(gesture_event);
+      // PinchBegin must always follow ScrollBegin.
+      if (InPinchGestureMode())
+        PinchBegin(gesture_event);
+      break;
+
+    case WebInputEvent::GestureScrollUpdate:
+      if (InPinchGestureMode()) {
+        // Convert scrolls to pinches while shift is pressed.
+        if (!pinch_gesture_active_)
+          PinchBegin(gesture_event);
+        else
+          PinchUpdate(gesture_event);
+      } else {
+        // Pass scroll update further. If shift was released, end the pinch.
+        if (pinch_gesture_active_)
+          PinchEnd(gesture_event);
+        client_->ForwardGestureEvent(gesture_event);
+      }
+      break;
+
+    case WebInputEvent::GestureScrollEnd:
+      // PinchEnd must precede ScrollEnd.
+      if (pinch_gesture_active_)
+        PinchEnd(gesture_event);
+      client_->ForwardGestureEvent(gesture_event);
+      break;
+
+    case WebInputEvent::GestureFlingStart:
+      // PinchEnd must precede FlingStart.
+      if (pinch_gesture_active_)
+        PinchEnd(gesture_event);
+      if (InPinchGestureMode()) {
+        // No fling in pinch mode. Forward scroll end instead of fling start.
+        suppress_next_fling_cancel_ = true;
+        ScrollEnd(gesture_event);
+      } else {
+        suppress_next_fling_cancel_ = false;
+        client_->ForwardGestureEvent(gesture_event);
+      }
+      break;
+
+    case WebInputEvent::GestureFlingCancel:
+      // If fling start was suppressed, we should not send fling cancel either.
+      if (!suppress_next_fling_cancel_)
+        client_->ForwardGestureEvent(gesture_event);
+      suppress_next_fling_cancel_ = false;
+      break;
+
+    default:
+      // Everything else goes through.
+      client_->ForwardGestureEvent(gesture_event);
+  }
+}
+
+void TouchEmulator::CancelTouch() {
+  if (!touch_active_)
+    return;
+
+  touch_event_.timeStampSeconds =
+      (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
+  touch_event_.type = WebInputEvent::TouchCancel;
+  touch_event_.touches[0].state = WebTouchPoint::StateCancelled;
+  touch_active_ = false;
+  if (gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_)))
+    client_->ForwardTouchEvent(touch_event_);
+}
+
+void TouchEmulator::UpdateCursor() {
+  if (!enabled_)
+    client_->SetCursor(pointer_cursor_);
+  else
+    client_->SetCursor(InPinchGestureMode() ? pinch_cursor_ : touch_cursor_);
+}
+
+bool TouchEmulator::UpdateShiftPressed(bool shift_pressed) {
+  if (shift_pressed_ == shift_pressed)
+    return false;
+  shift_pressed_ = shift_pressed;
+  UpdateCursor();
+  return true;
+}
+
+void TouchEmulator::PinchBegin(const WebGestureEvent& event) {
+  DCHECK(InPinchGestureMode());
+  DCHECK(!pinch_gesture_active_);
+  pinch_gesture_active_ = true;
+  pinch_anchor_ = gfx::Point(event.x, event.y);
+  pinch_scale_ = 1.f;
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchBegin;
+  client_->ForwardGestureEvent(pinch_event_);
+}
+
+void TouchEmulator::PinchUpdate(const WebGestureEvent& event) {
+  DCHECK(pinch_gesture_active_);
+  int dy = pinch_anchor_.y() - event.y;
+  float scale = exp(dy * 0.002f);
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchUpdate;
+  pinch_event_.data.pinchUpdate.scale = scale / pinch_scale_;
+  client_->ForwardGestureEvent(pinch_event_);
+  pinch_scale_ = scale;
+}
+
+void TouchEmulator::PinchEnd(const WebGestureEvent& event) {
+  DCHECK(pinch_gesture_active_);
+  pinch_gesture_active_ = false;
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchEnd;
+  client_->ForwardGestureEvent(pinch_event_);
+}
+
+void TouchEmulator::FillPinchEvent(const WebInputEvent& event) {
+  pinch_event_.timeStampSeconds = event.timeStampSeconds;
+  pinch_event_.modifiers = event.modifiers;
+  pinch_event_.sourceDevice = blink::WebGestureEvent::Touchscreen;
+  pinch_event_.x = pinch_anchor_.x();
+  pinch_event_.y = pinch_anchor_.y();
+}
+
+void TouchEmulator::ScrollEnd(const WebGestureEvent& event) {
+  WebGestureEvent scroll_event;
+  scroll_event.timeStampSeconds = event.timeStampSeconds;
+  scroll_event.modifiers = event.modifiers;
+  scroll_event.sourceDevice = blink::WebGestureEvent::Touchscreen;
+  scroll_event.type = WebInputEvent::GestureScrollEnd;
+  client_->ForwardGestureEvent(scroll_event);
+}
+
+bool TouchEmulator::FillTouchEventAndPoint(const WebMouseEvent& mouse_event) {
+  if (mouse_event.type != WebInputEvent::MouseDown &&
+      mouse_event.type != WebInputEvent::MouseMove &&
+      mouse_event.type != WebInputEvent::MouseUp) {
+    return false;
+  }
+
+  touch_event_.touchesLength = 1;
+  touch_event_.timeStampSeconds = mouse_event.timeStampSeconds;
+  touch_event_.modifiers = mouse_event.modifiers;
+
+  WebTouchPoint& point = touch_event_.touches[0];
+  point.id = 0;
+  point.radiusX = point.radiusY = 1.f;
+  point.force = 1.f;
+  point.rotationAngle = 0.f;
+  point.position.x = mouse_event.x;
+  point.screenPosition.x = mouse_event.globalX;
+  point.position.y = mouse_event.y;
+  point.screenPosition.y = mouse_event.globalY;
+
+  switch (mouse_event.type) {
+    case WebInputEvent::MouseDown:
+      touch_event_.type = WebInputEvent::TouchStart;
+      touch_active_ = true;
+      point.state = WebTouchPoint::StatePressed;
+      break;
+    case WebInputEvent::MouseMove:
+      touch_event_.type = WebInputEvent::TouchMove;
+      point.state = WebTouchPoint::StateMoved;
+      break;
+    case WebInputEvent::MouseUp:
+      touch_event_.type = WebInputEvent::TouchEnd;
+      touch_active_ = false;
+      point.state = WebTouchPoint::StateReleased;
+      break;
+    default:
+      NOTREACHED();
+  }
+  return true;
+}
+
+bool TouchEmulator::InPinchGestureMode() const {
+  return shift_pressed_ && allow_pinch_;
+}
+
+}  // namespace content
diff --git a/content/browser/renderer_host/input/touch_emulator.h b/content/browser/renderer_host/input/touch_emulator.h
new file mode 100644
index 0000000..b4b9e93
--- /dev/null
+++ b/content/browser/renderer_host/input/touch_emulator.h
@@ -0,0 +1,100 @@
+// Copyright 2014 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.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_
+
+#include "content/browser/renderer_host/input/touch_emulator_client.h"
+#include "content/common/cursors/webcursor.h"
+#include "content/port/common/input_event_ack_state.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+#include "ui/events/gesture_detection/filtered_gesture_provider.h"
+
+namespace content {
+
+// Emulates touch input with mouse and keyboard.
+class CONTENT_EXPORT TouchEmulator : public ui::GestureProviderClient {
+ public:
+  explicit TouchEmulator(TouchEmulatorClient* client);
+  virtual ~TouchEmulator();
+
+  void Enable(bool allow_pinch);
+  void Disable();
+
+  // Returns |true| if the event was consumed.
+  // TODO(dgozman): maybe pass latency info together with events.
+  bool HandleMouseEvent(const blink::WebMouseEvent& event);
+  bool HandleMouseWheelEvent(const blink::WebMouseWheelEvent& event);
+  bool HandleKeyboardEvent(const blink::WebKeyboardEvent& event);
+
+  // Returns |true| if the event ack was consumed. Consumed ack should not
+  // propagate any further.
+  bool HandleTouchEventAck(InputEventAckState ack_result);
+
+  // Cancel any touches, for example, when focus is lost.
+  void CancelTouch();
+
+ private:
+  // ui::GestureProviderClient implementation.
+  virtual void OnGestureEvent(const ui::GestureEventData& gesture) OVERRIDE;
+
+  void InitCursorFromResource(WebCursor* cursor, int resource_id);
+  void ResetState();
+  void UpdateCursor();
+  bool UpdateShiftPressed(bool shift_pressed);
+
+  // Whether we should convert scrolls into pinches.
+  bool InPinchGestureMode() const;
+
+  bool FillTouchEventAndPoint(const blink::WebMouseEvent& mouse_event);
+  void FillPinchEvent(const blink::WebInputEvent& event);
+
+  // The following methods generate and pass gesture events to the renderer.
+  void PinchBegin(const blink::WebGestureEvent& event);
+  void PinchUpdate(const blink::WebGestureEvent& event);
+  void PinchEnd(const blink::WebGestureEvent& event);
+  void ScrollEnd(const blink::WebGestureEvent& event);
+
+  TouchEmulatorClient* const client_;
+  ui::FilteredGestureProvider gesture_provider_;
+
+  // Disabled emulator does only process touch acks left from previous
+  // emulation. It does not intercept any events.
+  bool enabled_;
+  bool allow_pinch_;
+
+  // While emulation is on, default cursor is touch. Pressing shift changes
+  // cursor to the pinch one.
+  WebCursor pointer_cursor_;
+  WebCursor touch_cursor_;
+  WebCursor pinch_cursor_;
+
+  // These are used to drop extra mouse move events coming too quickly, so
+  // we don't handle too much touches in gesture provider.
+  bool last_mouse_event_was_move_;
+  double last_mouse_move_timestamp_;
+
+  bool mouse_pressed_;
+  bool shift_pressed_;
+
+  blink::WebTouchEvent touch_event_;
+  bool touch_active_;
+
+  // Whether we should suppress next fling cancel. This may happen when we
+  // did not send fling start in pinch mode.
+  bool suppress_next_fling_cancel_;
+
+  blink::WebGestureEvent pinch_event_;
+  // Point which does not move while pinch-zooming.
+  gfx::Point pinch_anchor_;
+  // The cumulative scale change from the start of pinch gesture.
+  float pinch_scale_;
+  bool pinch_gesture_active_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchEmulator);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_
diff --git a/content/browser/renderer_host/input/touch_emulator_client.h b/content/browser/renderer_host/input/touch_emulator_client.h
new file mode 100644
index 0000000..92f382f
--- /dev/null
+++ b/content/browser/renderer_host/input/touch_emulator_client.h
@@ -0,0 +1,26 @@
+// Copyright 2014 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.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_CLIENT_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_CLIENT_H_
+
+#include "content/common/content_export.h"
+#include "content/common/cursors/webcursor.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+// Emulates touch input with mouse and keyboard.
+class CONTENT_EXPORT TouchEmulatorClient {
+ public:
+  virtual ~TouchEmulatorClient() {}
+
+  virtual void ForwardGestureEvent(const blink::WebGestureEvent& event) = 0;
+  virtual void ForwardTouchEvent(const blink::WebTouchEvent& event) = 0;
+  virtual void SetCursor(const WebCursor& cursor) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_CLIENT_H_
diff --git a/content/browser/renderer_host/input/touch_emulator_unittest.cc b/content/browser/renderer_host/input/touch_emulator_unittest.cc
new file mode 100644
index 0000000..7593fb7
--- /dev/null
+++ b/content/browser/renderer_host/input/touch_emulator_unittest.cc
@@ -0,0 +1,318 @@
+// Copyright 2014 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 <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/time/time.h"
+#include "content/browser/renderer_host/input/touch_emulator.h"
+#include "content/browser/renderer_host/input/touch_emulator_client.h"
+#include "content/common/input/web_input_event_traits.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/events/gesture_detection/gesture_config_helper.h"
+
+#if defined(USE_AURA)
+#include "ui/aura/env.h"
+#include "ui/aura/test/test_screen.h"
+#endif
+
+using blink::WebGestureEvent;
+using blink::WebInputEvent;
+using blink::WebKeyboardEvent;
+using blink::WebMouseEvent;
+using blink::WebTouchEvent;
+using blink::WebTouchPoint;
+
+namespace content {
+
+class TouchEmulatorTest : public testing::Test,
+                          public TouchEmulatorClient {
+ public:
+  TouchEmulatorTest()
+      : shift_pressed_(false),
+        mouse_pressed_(false),
+        last_mouse_x_(-1),
+        last_mouse_y_(-1) {
+    last_event_time_seconds_ =
+        (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
+    event_time_delta_seconds_ = 0.1;
+  }
+
+  virtual ~TouchEmulatorTest() {}
+
+  // testing::Test
+  virtual void SetUp() OVERRIDE {
+#if defined(USE_AURA)
+    aura::Env::CreateInstance();
+    screen_.reset(aura::TestScreen::Create());
+    gfx::Screen::SetScreenInstance(gfx::SCREEN_TYPE_NATIVE, screen_.get());
+#endif
+
+    emulator_.reset(new TouchEmulator(this));
+    emulator_->Enable(true /* allow_pinch */);
+  }
+
+  virtual void TearDown() OVERRIDE {
+    emulator_->Disable();
+    EXPECT_EQ("", ExpectedEvents());
+
+#if defined(USE_AURA)
+    aura::Env::DeleteInstance();
+    screen_.reset();
+#endif
+  }
+
+  virtual void ForwardGestureEvent(
+      const blink::WebGestureEvent& event) OVERRIDE {
+    forwarded_events_.push_back(event.type);
+  }
+
+  virtual void ForwardTouchEvent(
+      const blink::WebTouchEvent& event) OVERRIDE {
+    forwarded_events_.push_back(event.type);
+    EXPECT_EQ(1U, event.touchesLength);
+    EXPECT_EQ(last_mouse_x_, event.touches[0].position.x);
+    EXPECT_EQ(last_mouse_y_, event.touches[0].position.y);
+    emulator()->HandleTouchEventAck(INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS);
+  }
+
+  virtual void SetCursor(const WebCursor& cursor) OVERRIDE {}
+
+ protected:
+  TouchEmulator* emulator() const {
+    return emulator_.get();
+  }
+
+  int modifiers() const {
+    return shift_pressed_ ? WebInputEvent::ShiftKey : 0;
+  }
+
+  std::string ExpectedEvents() {
+    std::string result;
+    for (size_t i = 0; i < forwarded_events_.size(); ++i) {
+      if (i != 0)
+        result += " ";
+      result += WebInputEventTraits::GetName(forwarded_events_[i]);
+    }
+    forwarded_events_.clear();
+    return result;
+  }
+
+  double GetNextEventTimeSeconds() {
+    last_event_time_seconds_ += event_time_delta_seconds_;
+    return last_event_time_seconds_;
+  }
+
+  void set_event_time_delta_seconds_(double delta) {
+    event_time_delta_seconds_ = delta;
+  }
+
+  void SendKeyboardEvent(WebInputEvent::Type type) {
+    WebKeyboardEvent event;
+    event.timeStampSeconds = GetNextEventTimeSeconds();
+    event.type = type;
+    event.modifiers = modifiers();
+    emulator()->HandleKeyboardEvent(event);
+  }
+
+  void PressShift() {
+    DCHECK(!shift_pressed_);
+    shift_pressed_ = true;
+    SendKeyboardEvent(WebInputEvent::KeyDown);
+  }
+
+  void ReleaseShift() {
+    DCHECK(shift_pressed_);
+    shift_pressed_ = false;
+    SendKeyboardEvent(WebInputEvent::KeyUp);
+  }
+
+  void SendMouseEvent(WebInputEvent::Type type, int  x, int y) {
+    WebMouseEvent event;
+    event.timeStampSeconds = GetNextEventTimeSeconds();
+    event.type = type;
+    event.button = mouse_pressed_ ? WebMouseEvent::ButtonLeft :
+        WebMouseEvent::ButtonNone;
+    event.modifiers = modifiers();
+    last_mouse_x_ = x;
+    last_mouse_y_ = y;
+    event.x = event.windowX = event.globalX = x;
+    event.y = event.windowY = event.globalY = y;
+    emulator()->HandleMouseEvent(event);
+  }
+
+  void MouseDown(int x, int y) {
+    DCHECK(!mouse_pressed_);
+    if (x != last_mouse_x_ || y != last_mouse_y_)
+      SendMouseEvent(WebInputEvent::MouseMove, x, y);
+    mouse_pressed_ = true;
+    SendMouseEvent(WebInputEvent::MouseDown, x, y);
+  }
+
+  void MouseDrag(int x, int y) {
+    DCHECK(mouse_pressed_);
+    SendMouseEvent(WebInputEvent::MouseMove, x, y);
+  }
+
+  void MouseMove(int x, int y) {
+    DCHECK(!mouse_pressed_);
+    SendMouseEvent(WebInputEvent::MouseMove, x, y);
+  }
+
+  void MouseUp(int x, int y) {
+    DCHECK(mouse_pressed_);
+    if (x != last_mouse_x_ || y != last_mouse_y_)
+      SendMouseEvent(WebInputEvent::MouseMove, x, y);
+    SendMouseEvent(WebInputEvent::MouseUp, x, y);
+    mouse_pressed_ = false;
+  }
+
+ private:
+  scoped_ptr<TouchEmulator> emulator_;
+  std::vector<WebInputEvent::Type> forwarded_events_;
+#if defined(USE_AURA)
+  scoped_ptr<gfx::Screen> screen_;
+#endif
+  double last_event_time_seconds_;
+  double event_time_delta_seconds_;
+  bool shift_pressed_;
+  bool mouse_pressed_;
+  int last_mouse_x_;
+  int last_mouse_y_;
+  base::MessageLoopForUI message_loop_;
+};
+
+
+TEST_F(TouchEmulatorTest, NoTouches) {
+  MouseMove(100, 200);
+  MouseMove(300, 300);
+  EXPECT_EQ("", ExpectedEvents());
+}
+
+TEST_F(TouchEmulatorTest, Touch) {
+  MouseMove(100, 200);
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDown(100, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseUp(200, 200);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate"
+      " TouchEnd GestureScrollEnd",
+      ExpectedEvents());
+}
+
+TEST_F(TouchEmulatorTest, MultipleTouches) {
+  MouseMove(100, 200);
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDown(100, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseUp(200, 200);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate"
+      " TouchEnd GestureScrollEnd",
+      ExpectedEvents());
+  MouseMove(300, 200);
+  MouseMove(200, 200);
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDown(300, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseDrag(300, 300);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      ExpectedEvents());
+  MouseDrag(300, 400);
+  EXPECT_EQ("TouchMove GestureScrollUpdate", ExpectedEvents());
+  MouseUp(300, 500);
+  EXPECT_EQ(
+      "TouchMove GestureScrollUpdate TouchEnd GestureScrollEnd",
+      ExpectedEvents());
+}
+
+TEST_F(TouchEmulatorTest, Pinch) {
+  MouseDown(100, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseDrag(200, 200);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      ExpectedEvents());
+  PressShift();
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDrag(300, 200);
+  EXPECT_EQ("TouchMove GesturePinchBegin", ExpectedEvents());
+  ReleaseShift();
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDrag(400, 200);
+  EXPECT_EQ(
+      "TouchMove GesturePinchEnd GestureScrollUpdate",
+      ExpectedEvents());
+  MouseUp(400, 200);
+  EXPECT_EQ("TouchEnd GestureScrollEnd", ExpectedEvents());
+}
+
+TEST_F(TouchEmulatorTest, DisableAndReenable) {
+  MouseDown(100, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseDrag(200, 200);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      ExpectedEvents());
+  PressShift();
+  MouseDrag(300, 200);
+  EXPECT_EQ("TouchMove GesturePinchBegin", ExpectedEvents());
+
+  // Disable while pinch is in progress.
+  emulator()->Disable();
+  EXPECT_EQ("TouchCancel GesturePinchEnd GestureScrollEnd", ExpectedEvents());
+  MouseUp(300, 200);
+  ReleaseShift();
+  MouseMove(300, 300);
+  EXPECT_EQ("", ExpectedEvents());
+
+  emulator()->Enable(true /* allow_pinch */);
+  MouseDown(300, 300);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  MouseDrag(300, 400);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      ExpectedEvents());
+
+  // Disable while scroll is in progress.
+  emulator()->Disable();
+  EXPECT_EQ("TouchCancel GestureScrollEnd", ExpectedEvents());
+}
+
+TEST_F(TouchEmulatorTest, MouseMovesDropped) {
+  MouseMove(100, 200);
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDown(100, 200);
+  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+
+  // Mouse move after mouse down is never dropped.
+  set_event_time_delta_seconds_(0.001);
+  MouseDrag(200, 200);
+  EXPECT_EQ(
+      "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      ExpectedEvents());
+
+  // The following mouse moves are dropped.
+  MouseDrag(300, 200);
+  EXPECT_EQ("", ExpectedEvents());
+  MouseDrag(350, 200);
+  EXPECT_EQ("", ExpectedEvents());
+
+  // Dispatching again.
+  set_event_time_delta_seconds_(0.1);
+  MouseDrag(400, 200);
+  EXPECT_EQ(
+      "TouchMove GestureScrollUpdate",
+      ExpectedEvents());
+  MouseUp(400, 200);
+  EXPECT_EQ(
+      "TouchEnd GestureScrollEnd",
+      ExpectedEvents());
+}
+
+}  // namespace content
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 32856f9..fc2b0ae 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -38,6 +38,7 @@
 #include "content/browser/renderer_host/input/synthetic_gesture_controller.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
 #include "content/browser/renderer_host/input/timeout_monitor.h"
+#include "content/browser/renderer_host/input/touch_emulator.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
@@ -239,6 +240,8 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
 
   input_router_.reset(new InputRouterImpl(process_, this, this, routing_id_));
 
+  touch_emulator_.reset();
+
 #if defined(USE_AURA)
   bool overscroll_enabled = CommandLine::ForCurrentProcess()->
       GetSwitchValueASCII(switches::kOverscrollHistoryNavigation) != "0";
@@ -479,6 +482,8 @@ bool RenderWidgetHostImpl::OnMessageReceived(const IPC::Message &msg) {
     IPC_MESSAGE_HANDLER(ViewHostMsg_Focus, OnFocus)
     IPC_MESSAGE_HANDLER(ViewHostMsg_Blur, OnBlur)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetCursor, OnSetCursor)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_SetTouchEventEmulationEnabled,
+                        OnSetTouchEventEmulationEnabled)
     IPC_MESSAGE_HANDLER(ViewHostMsg_TextInputTypeChanged,
                         OnTextInputTypeChanged)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ImeCancelComposition,
@@ -677,10 +682,16 @@ void RenderWidgetHostImpl::Blur() {
   if (overscroll_controller_)
     overscroll_controller_->Cancel();
 
+  if (touch_emulator_)
+    touch_emulator_->CancelTouch();
+
   Send(new InputMsg_SetFocus(routing_id_, false));
 }
 
 void RenderWidgetHostImpl::LostCapture() {
+  if (touch_emulator_)
+    touch_emulator_->CancelTouch();
+
   Send(new InputMsg_MouseCaptureLost(routing_id_));
 }
 
@@ -984,6 +995,9 @@ void RenderWidgetHostImpl::ForwardMouseEventWithLatencyInfo(
   if (IgnoreInputEvents())
     return;
 
+  if (touch_emulator_ && touch_emulator_->HandleMouseEvent(mouse_event))
+    return;
+
   input_router_->SendMouseEvent(MouseEventWithLatencyInfo(mouse_event,
                                                           latency_info));
 }
@@ -1007,6 +1021,9 @@ void RenderWidgetHostImpl::ForwardWheelEventWithLatencyInfo(
   if (IgnoreInputEvents())
     return;
 
+  if (touch_emulator_ && touch_emulator_->HandleMouseWheelEvent(wheel_event))
+    return;
+
   input_router_->SendWheelEvent(MouseWheelEventWithLatencyInfo(wheel_event,
                                                                latency_info));
 }
@@ -1056,6 +1073,11 @@ void RenderWidgetHostImpl::ForwardGestureEventWithLatencyInfo(
   input_router_->SendGestureEvent(gesture_with_latency);
 }
 
+void RenderWidgetHostImpl::ForwardTouchEvent(
+      const blink::WebTouchEvent& touch_event) {
+  ForwardTouchEventWithLatencyInfo(touch_event, ui::LatencyInfo());
+}
+
 void RenderWidgetHostImpl::ForwardTouchEventWithLatencyInfo(
       const blink::WebTouchEvent& touch_event,
       const ui::LatencyInfo& ui_latency) {
@@ -1131,6 +1153,9 @@ void RenderWidgetHostImpl::ForwardKeyboardEvent(
       suppress_next_char_events_ = false;
   }
 
+  if (touch_emulator_ && touch_emulator_->HandleKeyboardEvent(key_event))
+    return;
+
   input_router_->SendKeyboardEvent(
       key_event,
       CreateRWHLatencyInfoIfNotExist(NULL, key_event.type),
@@ -1151,6 +1176,12 @@ void RenderWidgetHostImpl::QueueSyntheticGesture(
   }
 }
 
+void RenderWidgetHostImpl::SetCursor(const WebCursor& cursor) {
+  if (!view_)
+    return;
+  view_->UpdateCursor(cursor);
+}
+
 void RenderWidgetHostImpl::SendCursorVisibilityState(bool is_visible) {
   Send(new InputMsg_CursorVisibilityChange(GetRoutingID(), is_visible));
 }
@@ -1815,10 +1846,19 @@ void RenderWidgetHostImpl::OnBlur() {
 }
 
 void RenderWidgetHostImpl::OnSetCursor(const WebCursor& cursor) {
-  if (!view_) {
-    return;
+  SetCursor(cursor);
+}
+
+void RenderWidgetHostImpl::OnSetTouchEventEmulationEnabled(
+    bool enabled, bool allow_pinch) {
+  if (enabled) {
+    if (!touch_emulator_)
+      touch_emulator_.reset(new TouchEmulator(this));
+    touch_emulator_->Enable(allow_pinch);
+  } else {
+    if (touch_emulator_)
+      touch_emulator_->Disable();
   }
-  view_->UpdateCursor(cursor);
 }
 
 void RenderWidgetHostImpl::OnTextInputTypeChanged(
@@ -2156,6 +2196,10 @@ void RenderWidgetHostImpl::OnTouchEventAck(
         ui::INPUT_EVENT_LATENCY_TERMINATED_TOUCH_COMPONENT, 0, 0);
   }
   ComputeTouchLatency(touch_event.latency);
+
+  if (touch_emulator_ && touch_emulator_->HandleTouchEventAck(ack_result))
+    return;
+
   if (view_)
     view_->ProcessAckedTouchEvent(touch_event, ack_result);
 }
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 1707018..6fb3203 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -26,6 +26,7 @@
 #include "content/browser/renderer_host/input/input_ack_handler.h"
 #include "content/browser/renderer_host/input/input_router_client.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
+#include "content/browser/renderer_host/input/touch_emulator_client.h"
 #include "content/common/input/synthetic_gesture_packet.h"
 #include "content/common/view_message_enums.h"
 #include "content/port/browser/event_with_latency_info.h"
@@ -84,6 +85,7 @@ class RenderWidgetHostDelegate;
 class RenderWidgetHostViewPort;
 class SyntheticGestureController;
 class TimeoutMonitor;
+class TouchEmulator;
 class WebCursor;
 struct EditCommand;
 
@@ -92,6 +94,7 @@ struct EditCommand;
 class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
                                             public InputRouterClient,
                                             public InputAckHandler,
+                                            public TouchEmulatorClient,
                                             public IPC::Listener {
  public:
   // routing_id can be MSG_ROUTING_NONE, in which case the next available
@@ -298,7 +301,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
 
   // Forwards the given message to the renderer. These are called by the view
   // when it has received a message.
-  void ForwardGestureEvent(const blink::WebGestureEvent& gesture_event);
   void ForwardGestureEventWithLatencyInfo(
       const blink::WebGestureEvent& gesture_event,
       const ui::LatencyInfo& ui_latency);
@@ -312,6 +314,13 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
       const blink::WebMouseWheelEvent& wheel_event,
       const ui::LatencyInfo& ui_latency);
 
+  // TouchEmulatorClient overrides.
+  virtual void ForwardGestureEvent(
+      const blink::WebGestureEvent& gesture_event) OVERRIDE;
+  virtual void ForwardTouchEvent(
+      const blink::WebTouchEvent& touch_event) OVERRIDE;
+  virtual void SetCursor(const WebCursor& cursor) OVERRIDE;
+
   // Queues a synthetic gesture for testing purposes.  Invokes the on_complete
   // callback when the gesture is finished running.
   void QueueSyntheticGesture(
@@ -658,6 +667,7 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   virtual void OnFocus();
   virtual void OnBlur();
   void OnSetCursor(const WebCursor& cursor);
+  void OnSetTouchEventEmulationEnabled(bool enabled, bool allow_pinch);
   void OnTextInputTypeChanged(ui::TextInputType type,
                               ui::TextInputMode input_mode,
                               bool can_compose_inline);
@@ -903,6 +913,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
 
   scoped_ptr<SyntheticGestureController> synthetic_gesture_controller_;
 
+  scoped_ptr<TouchEmulator> touch_emulator_;
+
   // Receives and handles all input events.
   scoped_ptr<InputRouter> input_router_;
 
diff --git a/content/browser/renderer_host/render_widget_host_unittest.cc b/content/browser/renderer_host/render_widget_host_unittest.cc
index 4dc6d24..08a26e8 100644
--- a/content/browser/renderer_host/render_widget_host_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_unittest.cc
@@ -48,6 +48,7 @@ using base::TimeDelta;
 using blink::WebGestureEvent;
 using blink::WebInputEvent;
 using blink::WebKeyboardEvent;
+using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
 using blink::WebTouchEvent;
 using blink::WebTouchPoint;
@@ -199,6 +200,7 @@ class MockRenderWidgetHost : public RenderWidgetHostImpl {
       : RenderWidgetHostImpl(delegate, process, routing_id, false),
         unresponsive_timer_fired_(false) {
     input_router_impl_ = static_cast<InputRouterImpl*>(input_router_.get());
+    acked_touch_event_type_ = blink::WebInputEvent::Undefined;
   }
 
   // Allow poking at a few private members.
@@ -261,6 +263,18 @@ class MockRenderWidgetHost : public RenderWidgetHostImpl {
     return touch_event_queue().empty();
   }
 
+  virtual void OnTouchEventAck(
+      const TouchEventWithLatencyInfo& event,
+      InputEventAckState ack_result) OVERRIDE {
+    // Sniff touch acks.
+    acked_touch_event_type_ = event.event.type;
+    RenderWidgetHostImpl::OnTouchEventAck(event, ack_result);
+  }
+
+  WebInputEvent::Type acked_touch_event_type() const {
+    return acked_touch_event_type_;
+  }
+
   bool ScrollStateIsContentScrolling() const {
     return scroll_state() == OverscrollController::STATE_CONTENT_SCROLLING;
   }
@@ -321,6 +335,7 @@ class MockRenderWidgetHost : public RenderWidgetHostImpl {
 
  private:
   bool unresponsive_timer_fired_;
+  WebInputEvent::Type acked_touch_event_type_;
 
   // |input_router_impl_| and |mock_input_router_| are owned by
   // RenderWidgetHostImpl.  The handles below are provided for convenience so
@@ -582,7 +597,10 @@ class RenderWidgetHostTest : public testing::Test {
   RenderWidgetHostTest()
       : process_(NULL),
         handle_key_press_event_(false),
-        handle_mouse_event_(false) {
+        handle_mouse_event_(false),
+        simulated_event_time_delta_seconds_(0) {
+    last_simulated_event_time_seconds_ =
+        (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
   }
   virtual ~RenderWidgetHostTest() {
   }
@@ -645,10 +663,20 @@ class RenderWidgetHostTest : public testing::Test {
     host_->OnMessageReceived(*response);
   }
 
+  double GetNextSimulatedEventTimeSeconds() {
+    last_simulated_event_time_seconds_ += simulated_event_time_delta_seconds_;
+    return last_simulated_event_time_seconds_;
+  }
+
   void SimulateKeyboardEvent(WebInputEvent::Type type) {
-  WebKeyboardEvent event = SyntheticWebKeyboardEventBuilder::Build(type);
-  NativeWebKeyboardEvent native_event;
-  memcpy(&native_event, &event, sizeof(event));
+    SimulateKeyboardEvent(type, 0);
+  }
+
+  void SimulateKeyboardEvent(WebInputEvent::Type type, int modifiers) {
+    WebKeyboardEvent event = SyntheticWebKeyboardEventBuilder::Build(type);
+    event.modifiers = modifiers;
+    NativeWebKeyboardEvent native_event;
+    memcpy(&native_event, &event, sizeof(event));
     host_->ForwardKeyboardEvent(native_event);
   }
 
@@ -679,11 +707,17 @@ class RenderWidgetHostTest : public testing::Test {
   }
 
   void SimulateMouseMove(int x, int y, int modifiers) {
-    host_->ForwardMouseEvent(
-        SyntheticWebMouseEventBuilder::Build(WebInputEvent::MouseMove,
-                                             x,
-                                             y,
-                                             modifiers));
+    SimulateMouseEvent(WebInputEvent::MouseMove, x, y, modifiers, false);
+  }
+
+  void SimulateMouseEvent(
+      WebInputEvent::Type type, int x, int y, int modifiers, bool pressed) {
+    WebMouseEvent event =
+        SyntheticWebMouseEventBuilder::Build(type, x, y, modifiers);
+    if (pressed)
+      event.button = WebMouseEvent::ButtonLeft;
+    event.timeStampSeconds = GetNextSimulatedEventTimeSeconds();
+    host_->ForwardMouseEvent(event);
   }
 
   void SimulateWheelEventWithPhase(WebMouseWheelEvent::Phase phase) {
@@ -788,6 +822,8 @@ class RenderWidgetHostTest : public testing::Test {
   scoped_ptr<gfx::Screen> screen_;
   bool handle_key_press_event_;
   bool handle_mouse_event_;
+  double last_simulated_event_time_seconds_;
+  double simulated_event_time_delta_seconds_;
 
  private:
   SyntheticWebTouchEvent touch_event_;
@@ -2381,6 +2417,203 @@ TEST_F(RenderWidgetHostTest, OverscrollResetsOnBlur) {
   process_->sink().ClearMessages();
 }
 
+std::string GetInputMessageTypes(RenderWidgetHostProcess* process) {
+  const WebInputEvent* event = NULL;
+  ui::LatencyInfo latency_info;
+  bool is_keyboard_shortcut;
+  std::string result;
+  for (size_t i = 0; i < process->sink().message_count(); ++i) {
+    const IPC::Message *message = process->sink().GetMessageAt(i);
+    EXPECT_EQ(InputMsg_HandleInputEvent::ID, message->type());
+    EXPECT_TRUE(InputMsg_HandleInputEvent::Read(
+        message, &event, &latency_info, &is_keyboard_shortcut));
+    if (i != 0)
+      result += " ";
+    result += WebInputEventTraits::GetName(event->type);
+  }
+  process->sink().ClearMessages();
+  return result;
+}
+
+TEST_F(RenderWidgetHostTest, TouchEmulator) {
+  simulated_event_time_delta_seconds_ = 0.1;
+  host_->DisableGestureDebounce();
+  // Immediately ack all touches instead of sending them to the renderer.
+  host_->OnMessageReceived(ViewHostMsg_HasTouchEventHandlers(0, false));
+  host_->OnMessageReceived(
+      ViewHostMsg_SetTouchEventEmulationEnabled(0, true, true));
+  process_->sink().ClearMessages();
+  view_->set_bounds(gfx::Rect(0, 0, 400, 200));
+  view_->Show();
+
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 10, 0, false);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Mouse press becomes touch start which in turn becomes tap.
+  SimulateMouseEvent(WebInputEvent::MouseDown, 10, 10, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchStart, host_->acked_touch_event_type());
+  EXPECT_EQ("GestureTapDown", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapDown,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+
+  // Mouse drag generates touch move, cancels tap and starts scroll.
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 30, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ(
+      "GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapCancel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Mouse drag with shift becomes pinch.
+  SimulateMouseEvent(
+      WebInputEvent::MouseMove, 10, 40, WebInputEvent::ShiftKey, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchBegin",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GesturePinchBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  SimulateMouseEvent(
+      WebInputEvent::MouseMove, 10, 50, WebInputEvent::ShiftKey, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchUpdate",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GesturePinchUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Mouse drag without shift becomes scroll again.
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 60, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchEnd GestureScrollUpdate",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 70, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GestureScrollUpdate",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  SimulateMouseEvent(WebInputEvent::MouseUp, 10, 70, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchEnd, host_->acked_touch_event_type());
+  EXPECT_EQ("GestureScrollEnd", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureScrollEnd,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Mouse move does nothing.
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 80, 0, false);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Another mouse down continues scroll.
+  SimulateMouseEvent(WebInputEvent::MouseDown, 10, 80, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchStart, host_->acked_touch_event_type());
+  EXPECT_EQ("GestureTapDown", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapDown,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 100, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ(
+      "GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapCancel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Another pinch.
+  SimulateMouseEvent(
+      WebInputEvent::MouseMove, 10, 110, WebInputEvent::ShiftKey, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchBegin",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GesturePinchBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  SimulateMouseEvent(
+      WebInputEvent::MouseMove, 10, 120, WebInputEvent::ShiftKey, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchUpdate",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GesturePinchUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Turn off emulation during a pinch.
+  host_->OnMessageReceived(
+      ViewHostMsg_SetTouchEventEmulationEnabled(0, false, false));
+  EXPECT_EQ(WebInputEvent::TouchCancel, host_->acked_touch_event_type());
+  EXPECT_EQ("GesturePinchEnd GestureScrollEnd",
+            GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GesturePinchEnd,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollEnd,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Mouse event should pass untouched.
+  SimulateMouseEvent(
+      WebInputEvent::MouseMove, 10, 10, WebInputEvent::ShiftKey, true);
+  EXPECT_EQ("MouseMove", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::MouseMove,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Turn on emulation.
+  host_->OnMessageReceived(
+      ViewHostMsg_SetTouchEventEmulationEnabled(0, true, true));
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Another touch.
+  SimulateMouseEvent(WebInputEvent::MouseDown, 10, 10, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchStart, host_->acked_touch_event_type());
+  EXPECT_EQ("GestureTapDown", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapDown,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+
+  // Scroll.
+  SimulateMouseEvent(WebInputEvent::MouseMove, 10, 30, 0, true);
+  EXPECT_EQ(WebInputEvent::TouchMove, host_->acked_touch_event_type());
+  EXPECT_EQ(
+      "GestureTapCancel GestureScrollBegin GestureScrollUpdate",
+      GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureTapCancel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+
+  // Turn off emulation during a scroll.
+  host_->OnMessageReceived(
+      ViewHostMsg_SetTouchEventEmulationEnabled(0, false, false));
+  EXPECT_EQ(WebInputEvent::TouchCancel, host_->acked_touch_event_type());
+
+  EXPECT_EQ("GestureScrollEnd", GetInputMessageTypes(process_));
+  SendInputEventACK(WebInputEvent::GestureScrollEnd,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+}
+
 #define TEST_InputRouterRoutes_NOARGS(INPUTMSG) \
   TEST_F(RenderWidgetHostTest, InputRouterRoutes##INPUTMSG) { \
     host_->SetupForInputRouterTest(); \
diff --git a/content/browser/resources/devtools/devtools_pinch_cursor.png b/content/browser/resources/devtools/devtools_pinch_cursor.png
new file mode 100644
index 0000000..8f057f0
--- /dev/null
+++ b/content/browser/resources/devtools/devtools_pinch_cursor.png
diff --git a/content/browser/resources/devtools/devtools_touch_cursor.png b/content/browser/resources/devtools/devtools_touch_cursor.png
new file mode 100644
index 0000000..f8d8a01
--- /dev/null
+++ b/content/browser/resources/devtools/devtools_touch_cursor.png
diff --git a/content/child/blink_platform_impl.cc b/content/child/blink_platform_impl.cc
index 9b2898e..237d2c8 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -701,6 +701,7 @@ const DataResource kDataResources[] = {
   { "generatePassword", IDR_PASSWORD_GENERATION_ICON, ui::SCALE_FACTOR_100P },
   { "generatePasswordHover",
     IDR_PASSWORD_GENERATION_ICON_HOVER, ui::SCALE_FACTOR_100P },
+  // TODO(dgozman): remove this after moving to content-based touch emulation.
   { "syntheticTouchCursor",
     IDR_SYNTHETIC_TOUCH_CURSOR, ui::SCALE_FACTOR_100P },
 };
diff --git a/content/common/view_messages.h b/content/common/view_messages.h
index 67dac64..5bb763a 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -1234,6 +1234,12 @@ IPC_MESSAGE_ROUTED1(ViewHostMsg_FocusedNodeChanged,
 
 IPC_MESSAGE_ROUTED1(ViewHostMsg_SetCursor, content::WebCursor)
 
+// Message sent from renderer requesting touch emulation using mouse.
+// Shift-scrolling should be converted to pinch, if |allow_pinch| is true.
+IPC_MESSAGE_ROUTED2(ViewHostMsg_SetTouchEventEmulationEnabled,
+                    bool /* enabled */,
+                    bool /* allow_pinch */)
+
 // Used to set a cookie. The cookie is set asynchronously, but will be
 // available to a subsequent ViewHostMsg_GetCookies request.
 IPC_MESSAGE_CONTROL4(ViewHostMsg_SetCookie,
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index c0ea977d..cbd0d38 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -932,6 +932,9 @@
     'browser/renderer_host/input/tap_suppression_controller_client.h',
     'browser/renderer_host/input/timeout_monitor.cc',
     'browser/renderer_host/input/timeout_monitor.h',
+    'browser/renderer_host/input/touch_emulator.cc',
+    'browser/renderer_host/input/touch_emulator.h',
+    'browser/renderer_host/input/touch_emulator_client.h',
     'browser/renderer_host/input/touch_event_queue.cc',
     'browser/renderer_host/input/touch_event_queue.h',
     'browser/renderer_host/input/touch_action_filter.cc',
diff --git a/content/content_resources.grd b/content/content_resources.grd
index e689fc6..408aa66 100644
--- a/content/content_resources.grd
+++ b/content/content_resources.grd
@@ -14,6 +14,8 @@
       <include name="IDR_ACCESSIBILITY_HTML" file="browser/resources/accessibility/accessibility.html" flattenhtml="true" allowexternalscript="true" type="BINDATA" />
       <include name="IDR_ACCESSIBILITY_CSS" file="browser/resources/accessibility/accessibility.css" type="BINDATA" />
       <include name="IDR_ACCESSIBILITY_JS" file="browser/resources/accessibility/accessibility.js" flattenhtml="true" type="BINDATA" />
+      <include name="IDR_DEVTOOLS_PINCH_CURSOR_ICON" file="browser/resources/devtools/devtools_pinch_cursor.png" type="BINDATA" />
+      <include name="IDR_DEVTOOLS_TOUCH_CURSOR_ICON" file="browser/resources/devtools/devtools_touch_cursor.png" type="BINDATA" />
       <include name="IDR_GPU_INTERNALS_HTML" file="browser/resources/gpu/gpu_internals.html" flattenhtml="true" allowexternalscript="true" type="BINDATA" />
       <include name="IDR_GPU_INTERNALS_JS" file="browser/resources/gpu/gpu_internals.js" flattenhtml="true" type="BINDATA" />
       <include name="IDR_INDEXED_DB_INTERNALS_HTML" file="browser/resources/indexed_db/indexeddb_internals.html" flattenhtml="true" allowexternalscript="true" type="BINDATA" />
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index c398612..ddc9d3e 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -479,6 +479,7 @@
         'browser/renderer_host/input/synthetic_gesture_controller_unittest.cc',
         'browser/renderer_host/input/tap_suppression_controller_unittest.cc',
         'browser/renderer_host/input/touch_action_filter_unittest.cc',
+        'browser/renderer_host/input/touch_emulator_unittest.cc',
         'browser/renderer_host/input/touch_event_queue_unittest.cc',
         'browser/renderer_host/media/audio_input_device_manager_unittest.cc',
         'browser/renderer_host/media/audio_renderer_host_unittest.cc',
diff --git a/content/renderer/devtools/devtools_agent.cc b/content/renderer/devtools/devtools_agent.cc
index 38b4b5e..3033733 100644
--- a/content/renderer/devtools/devtools_agent.cc
+++ b/content/renderer/devtools/devtools_agent.cc
@@ -251,6 +251,13 @@ void DevToolsAgent::disableDeviceEmulation() {
   impl->DisableScreenMetricsEmulation();
 }
 
+void DevToolsAgent::setTouchEventEmulationEnabled(
+    bool enabled, bool allow_pinch) {
+  RenderViewImpl* impl = static_cast<RenderViewImpl*>(render_view());
+  impl->Send(new ViewHostMsg_SetTouchEventEmulationEnabled(
+      impl->routing_id(), enabled, allow_pinch));
+}
+
 #if defined(USE_TCMALLOC) && !defined(OS_WIN)
 static void AllocationVisitor(void* data, const void* ptr) {
     typedef blink::WebDevToolsAgentClient::AllocatedObjectVisitor Visitor;
diff --git a/content/renderer/devtools/devtools_agent.h b/content/renderer/devtools/devtools_agent.h
index fed4a68..9d58d97 100644
--- a/content/renderer/devtools/devtools_agent.h
+++ b/content/renderer/devtools/devtools_agent.h
@@ -76,6 +76,7 @@ class DevToolsAgent : public RenderViewObserver,
   virtual void enableDeviceEmulation(
       const blink::WebDeviceEmulationParams& params);
   virtual void disableDeviceEmulation();
+  virtual void setTouchEventEmulationEnabled(bool enabled, bool allow_pinch);
 
   void OnAttach();
   void OnReattach(const std::string& agent_state);