[DevTools] Handle emulation in embedder, call into web API.

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 8c5c6d6893bfbfd4f368e714bfa72c5c94e0759e..e279288312a14f3b3890e5bce4ba4481cd50ea4f 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -248,7 +248,7 @@ class RenderWidget::ScreenMetricsEmulator {
   // Scale and offset used to convert between host coordinates
   // and webwidget coordinates.
   float scale() { return scale_; }
-  gfx::Point offset() { return offset_; }
+  gfx::PointF offset() { return offset_; }
   gfx::Rect applied_widget_rect() const { return applied_widget_rect_; }
   gfx::Rect original_screen_rect() const { return original_view_screen_rect_; }
   const WebScreenInfo& original_screen_info() { return original_screen_info_; }
@@ -278,7 +278,7 @@ class RenderWidget::ScreenMetricsEmulator {
 
   // The computed scale and offset used to fit widget into browser window.
   float scale_;
-  gfx::Point offset_;
+  gfx::PointF offset_;
 
   // Widget rect as passed to webwidget.
   gfx::Rect applied_widget_rect_;
@@ -314,7 +314,7 @@ RenderWidget::ScreenMetricsEmulator::~ScreenMetricsEmulator() {
   widget_->screen_info_ = original_screen_info_;
 
   widget_->SetDeviceScaleFactor(original_screen_info_.deviceScaleFactor);
-  widget_->SetScreenMetricsEmulationParameters(0.f, gfx::Point(), 1.f);
+  widget_->SetScreenMetricsEmulationParameters(false, params_);
   widget_->view_screen_rect_ = original_view_screen_rect_;
   widget_->window_screen_rect_ = original_window_screen_rect_;
   widget_->Resize(original_size_,
@@ -392,8 +392,11 @@ void RenderWidget::ScreenMetricsEmulator::Apply(
   //   even when emulating different scale factor;
   // - in order to fit into view, WebView applies offset and scale to the
   //   root layer.
-  widget_->SetScreenMetricsEmulationParameters(
-      original_screen_info_.deviceScaleFactor, offset_, scale_);
+  blink::WebDeviceEmulationParams modified_params = params_;
+  modified_params.deviceScaleFactor = original_screen_info_.deviceScaleFactor;
+  modified_params.offset = blink::WebFloatPoint(offset_.x(), offset_.y());
+  modified_params.scale = scale_;
+  widget_->SetScreenMetricsEmulationParameters(true, modified_params);
 
   widget_->SetDeviceScaleFactor(applied_device_scale_factor);
   widget_->view_screen_rect_ = applied_widget_rect_;
@@ -686,9 +689,8 @@ gfx::Rect RenderWidget::AdjustValidationMessageAnchor(const gfx::Rect& anchor) {
 }
 
 void RenderWidget::SetScreenMetricsEmulationParameters(
-    float device_scale_factor,
-    const gfx::Point& root_layer_offset,
-    float root_layer_scale) {
+    bool enabled,
+    const blink::WebDeviceEmulationParams& params) {
   // This is only supported in RenderView.
   NOTREACHED();
 }