Compute the popup location/size correctly when use-zoom-for-dsf is enabled.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 9a8aaf1e0201b97512c4fdce21c358c84732f9cd..642108eae7a0d9b0b59d572f1332f217aa05a15f 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -828,9 +828,8 @@ void RenderWidget::Resize(const gfx::Size& new_size,
   WebSize visual_viewport_size;
 
   if (IsUseZoomForDSFEnabled()) {
-    gfx::SizeF scaled_visible_viewport_size =
-        gfx::ScaleSize(gfx::SizeF(visible_viewport_size), device_scale_factor_);
-    visual_viewport_size = gfx::ToCeiledSize(scaled_visible_viewport_size);
+    visual_viewport_size =
+        gfx::ScaleToCeiledSize(visible_viewport_size, device_scale_factor_);
   } else {
     visual_viewport_size = visible_viewport_size_;
   }
@@ -1371,7 +1370,7 @@ void RenderWidget::initializeLayerTreeView() {
 
   compositor_ = RenderWidgetCompositor::Create(this, compositor_deps_);
   compositor_->setViewportSize(physical_backing_size_);
-
+  OnDeviceScaleFactorChanged();
   // For background pages and certain tests, we don't want to trigger
   // OutputSurface creation.
   if (compositor_never_visible_ || !RenderThreadImpl::current())
@@ -1627,9 +1626,8 @@ void RenderWidget::setToolTipText(const blink::WebString& text,
   Send(new ViewHostMsg_SetTooltipText(routing_id_, text, hint));
 }
 
-void RenderWidget::setWindowRect(const WebRect& rect) {
-  // TODO(oshima): Scale back to DIP coordinates.
-  WebRect window_rect = rect;
+void RenderWidget::setWindowRect(const WebRect& rect_in_screen) {
+  WebRect window_rect = rect_in_screen;
   if (popup_origin_scale_for_emulation_) {
     float scale = popup_origin_scale_for_emulation_;
     window_rect.x = popup_screen_origin_for_emulation_.x() +
@@ -1707,6 +1705,14 @@ void RenderWidget::OnImeConfirmComposition(const base::string16& text,
   UpdateCompositionInfo(true);
 }
 
+void RenderWidget::OnDeviceScaleFactorChanged() {
+  DCHECK(compositor_);
+    if (IsUseZoomForDSFEnabled())
+      compositor_->SetPaintedDeviceScaleFactor(device_scale_factor_);
+    else
+      compositor_->setDeviceScaleFactor(device_scale_factor_);
+}
+
 void RenderWidget::OnRepaint(gfx::Size size_to_paint) {
   // During shutdown we can just ignore this message.
   if (!webwidget_)
@@ -1757,6 +1763,25 @@ void RenderWidget::showImeIfNeeded() {
   OnShowImeIfNeeded();
 }
 
+void RenderWidget::convertViewportToScreen(blink::WebRect* rect) {
+  gfx::Rect screen_rect(*rect);
+  if (IsUseZoomForDSFEnabled()) {
+    // TODO(oshima): We may need to allow pixel precision here as the the
+    // anchor element can be placed at half pixel.
+    float reverse = 1 / device_scale_factor_;
+    screen_rect.set_origin(
+        gfx::ScaleToRoundedPoint(screen_rect.origin(), reverse));
+    screen_rect.set_size(gfx::ScaleToRoundedSize(screen_rect.size(), reverse));
+  }
+
+  blink::WebRect window_rect = windowRect();
+  screen_rect.Offset(window_rect.x, window_rect.y);
+  rect->x = screen_rect.x();
+  rect->y = screen_rect.y();
+  rect->width = screen_rect.width();
+  rect->height = screen_rect.height();
+}
+
 void RenderWidget::OnShowImeIfNeeded() {
 #if defined(OS_ANDROID) || defined(USE_AURA)
   UpdateTextInputState(SHOW_IME_IF_NEEDED, FROM_NON_IME);
@@ -1823,6 +1848,9 @@ void RenderWidget::SetDeviceScaleFactor(float device_scale_factor) {
     return;
 
   device_scale_factor_ = device_scale_factor;
+
+  OnDeviceScaleFactorChanged();
+
   ScheduleComposite();
 }