Implementation of device metrics emulation in render view.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
===================================================================
--- content/renderer/render_widget.cc	(revision 221161)
+++ content/renderer/render_widget.cc	(working copy)
@@ -53,7 +53,7 @@
 #include "third_party/WebKit/public/web/WebScreenInfo.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "ui/base/ui_base_switches.h"
-#include "ui/gfx/point.h"
+#include "ui/gfx/point_conversions.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/skia_util.h"
@@ -79,6 +79,7 @@
 using WebKit::WebInputEvent;
 using WebKit::WebKeyboardEvent;
 using WebKit::WebMouseEvent;
+using WebKit::WebMouseWheelEvent;
 using WebKit::WebNavigationPolicy;
 using WebKit::WebPagePopup;
 using WebKit::WebPoint;
@@ -186,6 +187,280 @@
 
 namespace content {
 
+// RenderWidget::DeviceEmulator ------------------------------------------------
+
+class RenderWidget::DeviceEmulator {

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

I suggest renaming this to ScreenMetricsEmulator.  And basically everywhere else
that says "device" in this patch I'd like to have renamed to "screen metrics",
since that wording is more specific.

[dgozman, 2013/09/27 19:02:03]

Done. I've left "device" in Blink API though, as "device emulation" is already
heavily used there.

+ public:
+  DeviceEmulator(const gfx::Size& device_size,
+                             const gfx::Rect& widget_rect,

[pfeldman, 2013/09/19 17:27:16]

Poor indent.

[dgozman, 2013/09/27 19:02:03]

Done.

+                             float device_scale_factor,
+                             bool fit_to_view);
+  virtual ~DeviceEmulator();
+
+  base::WeakPtr<DeviceEmulator> AsWeakPtr();
+
+  void BeginEmulation(RenderWidget* widget);

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

If it's always the same RenderWidget, can we just pass it in the constructor and
keep it in a member variable?

[dgozman, 2013/09/27 19:02:03]

Done.

+  void ChangeEmulationParams(RenderWidget* widget,
+                             DeviceEmulator* params);
+  void EndEmulation(RenderWidget* widget);
+
+  // The following methods alter handlers' behavior for messages related to
+  // widget size and position.
+  void OnResizeMessage(RenderWidget* widget,
+                       const ViewMsg_Resize_Params& params);
+  void OnUpdateScreenRectsMessage(RenderWidget* widget,
+                                  const gfx::Rect view_screen_rect,
+                                  const gfx::Rect window_screen_rect);
+  void OnShowContextMenu(RenderWidget* widget, ContextMenuParams* params);
+
+  WebKit::WebInputEvent* ConvertInputEventToEmulated(
+      RenderWidget* widget, const WebKit::WebInputEvent* event);
+
+  // Created popups need to be repositioned.
+  WebKit::WebRect ConvertPopupScreenRectFromEmulated(
+      RenderWidget* popup, const WebKit::WebRect& rect);
+
+ private:
+  void Apply(RenderWidget* widget, float overdraw_bottom_height,
+      gfx::Rect resizer_rect, bool is_fullscreen);
+  void ConvertMouseEventToEmulated(WebKit::WebMouseEvent* event);
+  void ConvertTouchPointToEmulated(WebKit::WebTouchPoint* point);
+
+  // Parameters as passed by WebViewClient::EmulateDevice.
+  gfx::Size device_size_;
+  gfx::Rect widget_rect_;
+  float device_scale_factor_;
+  bool fit_to_view_;
+
+  // The computed scaled used to fit widget into browser window.
+  float scale_;
+
+  // Original values to restore back after emulation ends.
+  gfx::Size original_size_;
+  gfx::Size original_physical_backing_size_;
+  WebKit::WebScreenInfo original_screen_info_;
+  gfx::Rect original_view_screen_rect_;
+  gfx::Rect original_window_screen_rect_;
+
+  base::WeakPtrFactory<DeviceEmulator> weak_ptr_factory_;
+};
+
+RenderWidget::DeviceEmulator::DeviceEmulator(
+    const gfx::Size& device_size,
+    const gfx::Rect& widget_rect,
+    float device_scale_factor,
+    bool fit_to_view)

[pfeldman, 2013/09/19 17:27:16]

scale_ is not initialized.

[dgozman, 2013/09/27 19:02:03]

Done.

+    : device_size_(device_size),
+      widget_rect_(widget_rect),
+      device_scale_factor_(device_scale_factor),
+      fit_to_view_(fit_to_view),
+      weak_ptr_factory_(this) {
+}
+
+RenderWidget::DeviceEmulator::~DeviceEmulator() {
+}
+
+void RenderWidget::DeviceEmulator::BeginEmulation(RenderWidget* widget) {
+  original_size_ = widget->size_;
+  original_physical_backing_size_ = widget->physical_backing_size_;
+  original_screen_info_ = widget->screen_info_;
+  original_view_screen_rect_ = widget->view_screen_rect_;
+  original_window_screen_rect_ = widget->window_screen_rect_;
+  Apply(widget, widget->overdraw_bottom_height_,
+        widget->resizer_rect_, widget->is_fullscreen_);
+}
+
+void RenderWidget::DeviceEmulator::ChangeEmulationParams(
+    RenderWidget* widget, DeviceEmulator* params) {
+  device_size_ = params->device_size_;
+  widget_rect_ = params->widget_rect_;
+  device_scale_factor_ = params->device_scale_factor_;
+  fit_to_view_ = params->fit_to_view_;
+  Apply(widget, widget->overdraw_bottom_height_,
+        widget->resizer_rect_, widget->is_fullscreen_);
+}
+
+void RenderWidget::DeviceEmulator::EndEmulation(RenderWidget* widget) {
+  widget->screen_info_ = original_screen_info_;
+
+  widget->Send(new ViewHostMsg_SetExpectedSize(widget->routing_id(),
+      gfx::Size()));
+
+  widget->SetDeviceScaleFactor(original_screen_info_.deviceScaleFactor);
+  widget->SetDeviceEmulationParameters(false /* enabled */, 1.f, 1.f);
+  widget->view_screen_rect_ = original_view_screen_rect_;
+  widget->window_screen_rect_ = original_window_screen_rect_;
+  widget->Resize(original_size_, original_physical_backing_size_,
+      widget->overdraw_bottom_height_, widget->resizer_rect_,
+      widget->is_fullscreen_, NO_RESIZE_ACK);
+}
+
+void RenderWidget::DeviceEmulator::Apply(RenderWidget* widget,
+    float overdraw_bottom_height, gfx::Rect resizer_rect, bool is_fullscreen) {
+  if (fit_to_view_) {
+    float width_ratio = !original_size_.width() ? 1.f :
+       static_cast<float>(widget_rect_.width()) / original_size_.width();
+    float height_ratio = !original_size_.height() ? 1.f :
+        static_cast<float>(widget_rect_.height()) / original_size_.height();
+    float ratio = std::max(1.0f, std::max(width_ratio, height_ratio));
+    scale_ = 1.f / ratio;
+  } else {
+    scale_ = 1.f;
+  }
+
+  widget->screen_info_.rect = gfx::Rect(device_size_);
+  widget->screen_info_.availableRect = gfx::Rect(device_size_);
+  widget->screen_info_.deviceScaleFactor = device_scale_factor_;
+
+  // Pass two emulation parameters to the blink side:
+  // - we keep the real device scale factor in compositor to produce sharp image
+  //   even when emulating different scale factor;
+  // - in order to fit into view, WebView applies scaling transform to the
+  //   root layer.
+  widget->SetDeviceEmulationParameters(true /* enabled */,
+      original_screen_info_.deviceScaleFactor, scale_);
+
+  widget->SetDeviceScaleFactor(device_scale_factor_);
+  widget->view_screen_rect_ = widget_rect_;
+  widget->window_screen_rect_ = widget->screen_info_.availableRect;
+
+  // Make host accept an image of different size.
+  widget->Send(new ViewHostMsg_SetExpectedSize(widget->routing_id(),
+      gfx::ToCeiledSize(gfx::ScaleSize(widget_rect_.size(), scale_))));
+
+  gfx::Size physical_backing_size = gfx::ToCeiledSize(gfx::ScaleSize(
+      widget_rect_.size(), original_screen_info_.deviceScaleFactor * scale_));
+  widget->Resize(widget_rect_.size(), physical_backing_size,
+      overdraw_bottom_height, resizer_rect, is_fullscreen, NO_RESIZE_ACK);
+}
+
+void RenderWidget::DeviceEmulator::OnResizeMessage(
+    RenderWidget* widget, const ViewMsg_Resize_Params& params) {
+  bool need_ack = params.new_size != original_size_;
+  original_size_ = params.new_size;
+  original_physical_backing_size_ = params.physical_backing_size;
+  original_screen_info_ = params.screen_info;
+  Apply(widget, params.overdraw_bottom_height, params.resizer_rect,
+        params.is_fullscreen);
+
+  if (need_ack) {
+    widget->set_next_paint_is_resize_ack();
+    if (widget->is_accelerated_compositing_active_ && widget->compositor_)
+      widget->compositor_->SetNeedsRedrawRect(gfx::Rect(widget->size_));
+    else
+      widget->didInvalidateRect(gfx::Rect(widget->size_));

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

I thought accelerated compositing was mandatory for device emulation support? 
Is this line needed?

[dgozman, 2013/09/27 19:02:03]

You are right. Removed.

+  }
+}
+
+void RenderWidget::DeviceEmulator::OnUpdateScreenRectsMessage(
+    RenderWidget* widget,
+    const gfx::Rect view_screen_rect,
+    const gfx::Rect window_screen_rect) {
+  original_view_screen_rect_ = view_screen_rect;
+  original_window_screen_rect_ = window_screen_rect;
+  widget->Send(new ViewHostMsg_UpdateScreenRects_ACK(widget->routing_id()));
+}
+
+void RenderWidget::DeviceEmulator::OnShowContextMenu(
+    RenderWidget* widget, ContextMenuParams* params) {
+  params->x *= scale_;
+  params->y *= scale_;
+}
+
+WebInputEvent* RenderWidget::DeviceEmulator::ConvertInputEventToEmulated(

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

It's the job of Source/web/WebInputEventConversion.cpp in Blink to apply
translation and scale due to scroll offset and pageScaleFactor.  It seems to me
you're doing a very similar thing here (and probably missing a few subtleties
that are applied correctly there) and you should find a way to get your extra
scale factor applied there instead.

For scale, perhaps simply adjusting the return value of
FrameView::visibleContentScaleFactor() would do what you need?  And again I'm
not sure what you're trying to achieve exactly by changing the screen positions
by widgetRect so I suggest deleting that part and forgetting about it.  (It's an
"emulated" environment anyway, we're under no obligation to give it accurate
screen position?)

[dgozman, 2013/09/27 19:02:03]

Done. Please see https://codereview.chromium.org/23187005/ for implementation
details.

+    RenderWidget* widget, const WebInputEvent* event) {
+  if (!event)
+    return NULL;
+
+  if (WebInputEvent::isKeyboardEventType(event->type)) {
+    const WebKeyboardEvent& keyboard_event =
+            *static_cast<const WebKeyboardEvent*>(event);
+    WebKeyboardEvent* result = new WebKeyboardEvent(keyboard_event);

[pfeldman, 2013/09/19 17:27:16]

return new ...

[dgozman, 2013/09/27 19:02:03]

Done.

+    return result;
+  }
+
+  if (WebInputEvent::isMouseEventType(event->type)) {
+    const WebMouseEvent& mouse_event =
+            *static_cast<const WebMouseEvent*>(event);
+    WebMouseEvent* result = new WebMouseEvent(mouse_event);
+    ConvertMouseEventToEmulated(result);
+    return result;
+  }
+
+  if (WebInputEvent::MouseWheel == event->type) {
+    const WebMouseWheelEvent& mouse_wheel_event =
+            *static_cast<const WebMouseWheelEvent*>(event);
+    WebMouseWheelEvent* result = new WebMouseWheelEvent(mouse_wheel_event);
+    ConvertMouseEventToEmulated(result);
+    return result;
+  }
+
+  if (WebInputEvent::isGestureEventType(event->type)) {
+    const WebGestureEvent& gesture_event =
+            *static_cast<const WebGestureEvent*>(event);
+    WebGestureEvent* result = new WebGestureEvent(gesture_event);
+    result->x = 1.f / scale_ * result->x;
+    result->y = 1.f / scale_ * result->y;
+    result->globalX = widget_rect_.x() + result->x;
+    result->globalY = widget_rect_.y() + result->y;
+    return result;
+  }
+
+  if (WebInputEvent::isTouchEventType(event->type)) {
+    const WebTouchEvent& touch_event =
+            *static_cast<const WebTouchEvent*>(event);
+    WebTouchEvent* result = new WebTouchEvent(touch_event);
+    for (size_t index = 0; index < result->touchesLength; ++index) {

[pfeldman, 2013/09/19 17:27:16]

One line blocks don't need {}

[dgozman, 2013/09/27 19:02:03]

Done.

+      ConvertTouchPointToEmulated(&result->touches[index]);
+    }
+    for (size_t index = 0; index < result->changedTouchesLength; ++index) {
+      ConvertTouchPointToEmulated(&result->changedTouches[index]);
+    }
+    for (size_t index = 0; index < result->targetTouchesLength; ++index) {
+      ConvertTouchPointToEmulated(&result->targetTouches[index]);
+    }
+    return result;
+  }
+
+  return NULL;
+}
+
+void RenderWidget::DeviceEmulator::ConvertMouseEventToEmulated(
+    WebKit::WebMouseEvent* event) {
+  event->x = 1.f / scale_ * event->x;
+  event->y = 1.f / scale_ * event->y;
+  event->movementX = 1.f / scale_ * event->movementX;
+  event->movementY = 1.f / scale_ * event->movementY;
+  event->windowX = widget_rect_.x() + event->x;
+  event->windowY = widget_rect_.y() + event->y;
+  event->globalX = event->windowX;
+  event->globalY = event->windowY;
+}
+
+void RenderWidget::DeviceEmulator::ConvertTouchPointToEmulated(
+    WebKit::WebTouchPoint* point) {
+  point->position.x = 1.f / scale_ * point->position.x;
+  point->position.y = 1.f / scale_ * point->position.y;
+  point->screenPosition.x = widget_rect_.x() + point->position.x;
+  point->screenPosition.y = widget_rect_.y() + point->position.y;
+}
+
+base::WeakPtr<RenderWidget::DeviceEmulator> RenderWidget::DeviceEmulator::AsWeakPtr() {

[pfeldman, 2013/09/19 17:27:16]

80 chars limit please.

base::WeakPtr<RenderWidget::DeviceEmulator>
RenderWidget::DeviceEmulator::AsWeakPtr() {
  ...
}

[dgozman, 2013/09/27 19:02:03]

Done.

+  return weak_ptr_factory_.GetWeakPtr();
+}
+
+WebKit::WebRect RenderWidget::DeviceEmulator::ConvertPopupScreenRectFromEmulated(

[pfeldman, 2013/09/19 17:27:16]

ditto

[dgozman, 2013/09/27 19:02:03]

Done.

+    RenderWidget* popup, const WebKit::WebRect& rect) {
+  WebKit::WebRect result = rect;
+  result.x = original_view_screen_rect_.x() +
+      (result.x - widget_rect_.x()) * scale_;
+  result.y = original_view_screen_rect_.y() +
+      (result.y - widget_rect_.y()) * scale_;
+  return result;
+}
+
+// RenderWidget ----------------------------------------------------------------
+
 RenderWidget::RenderWidget(WebKit::WebPopupType popup_type,
                            const WebKit::WebScreenInfo& screen_info,
                            bool swapped_out,
@@ -368,6 +643,45 @@
 #endif
 }
 
+void RenderWidget::EmulateDevice(
+    bool enabled,
+    const gfx::Size& device_size,
+    const gfx::Rect& widget_rect,
+    float device_scale_factor,
+    bool fit_to_view) {
+  if (enabled) {
+    DeviceEmulator* helper = new DeviceEmulator(device_size, widget_rect,
+        device_scale_factor, fit_to_view);
+
+    if (!device_emulator_) {
+      device_emulator_.reset(helper);
+      device_emulator_->BeginEmulation(this);

[pfeldman, 2013/09/19 17:27:16]

I prefer StartEmulation / UpdateEmulation / StopEmulation.

[dgozman, 2013/09/27 19:02:03]

BeginEmulation/EndEmulation are removed.
I'd keep ChangeEmulationParams as it's the only remaining method.

+    } else {
+      device_emulator_->ChangeEmulationParams(this, helper);

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

You're leaking the "helper" object" in this codepath.  I suggest not doing it
this way and just pass the four arguments to ChangeEmulationParams.

[dgozman, 2013/09/27 19:02:03]

Done.

+    }
+  } else {
+    if (device_emulator_)
+      device_emulator_->EndEmulation(this);

[aelias_OOO_until_Jul13, 2013/09/20 07:10:14]

Doesn't look like keeping BeginEmulation/EndEmulation separate is useful, please
merge them into the constructor and destructor.

[dgozman, 2013/09/27 19:02:03]

Done.

+    device_emulator_.reset();
+  }
+}
+
+void RenderWidget::SetDeviceEmulationParameters(
+    bool enabled, float device_scale_factor, float root_layer_scale) {
+  // This is only supported in RenderView.
+  NOTREACHED();
+}
+
+void RenderWidget::OnShowHostContextMenu(ContextMenuParams* params) {
+  if (device_emulator_)
+    device_emulator_->OnShowContextMenu(this, params);
+}
+
+void RenderWidget::set_popup_device_emulator(
+    RenderWidget::DeviceEmulator *emulator) {
+  popup_device_emulator_ = emulator->AsWeakPtr();
+}
+
 bool RenderWidget::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(RenderWidget, message)
@@ -531,6 +845,11 @@
 }
 
 void RenderWidget::OnResize(const ViewMsg_Resize_Params& params) {
+  if (device_emulator_) {
+    device_emulator_->OnResizeMessage(this, params);
+    return;
+  }
+
   screen_info_ = params.screen_info;
   SetDeviceScaleFactor(screen_info_.deviceScaleFactor);
   Resize(params.new_size, params.physical_backing_size,
@@ -813,6 +1132,15 @@
                                       const ui::LatencyInfo& latency_info,
                                       bool is_keyboard_shortcut) {
   handling_input_event_ = true;
+
+  scoped_ptr<const WebKit::WebInputEvent> owner;
+  if (device_emulator_) {
+    input_event = device_emulator_->ConvertInputEventToEmulated(
+        this, input_event);
+    if (input_event)
+      owner.reset(input_event);

[pfeldman, 2013/09/19 17:27:16]

You can reset unconditionally.

[dgozman, 2013/09/27 19:02:03]

Removed.

+  }
+
   if (!input_event) {
     handling_input_event_ = false;
     return;
@@ -1776,7 +2104,13 @@
   Send(new ViewHostMsg_SetTooltipText(routing_id_, text, hint));
 }
 
-void RenderWidget::setWindowRect(const WebRect& pos) {
+void RenderWidget::setWindowRect(const WebRect& rect) {
+  WebRect pos = rect;
+  if (popup_device_emulator_) {
+    pos = popup_device_emulator_->ConvertPopupScreenRectFromEmulated(
+        this, rect);
+  }
+
   if (did_show_) {
     if (!RenderThreadImpl::current()->layout_test_mode()) {
       Send(new ViewHostMsg_RequestMove(routing_id_, pos));
@@ -2017,6 +2351,11 @@
 
 void RenderWidget::OnUpdateScreenRects(const gfx::Rect& view_screen_rect,
                                        const gfx::Rect& window_screen_rect) {
+  if (device_emulator_) {
+    device_emulator_->OnUpdateScreenRectsMessage(
+        this, view_screen_rect, window_screen_rect);
+    return;
+  }
   view_screen_rect_ = view_screen_rect;
   window_screen_rect_ = window_screen_rect;
   Send(new ViewHostMsg_UpdateScreenRects_ACK(routing_id()));