Wires through scale factor and bounds in html_viewer

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/1018543002

Cr-Commit-Position: refs/heads/master@{#320998}

mojo/services/html_viewer/BUILD.gn

@@ -98,6 +98,7 @@ source_set("lib") {
     "//third_party/mojo_services/src/input_events/public/interfaces",
     "//third_party/mojo_services/src/navigation/public/interfaces",
     "//third_party/mojo_services/src/surfaces/public/interfaces",
+    "//ui/gfx/geometry",
     "//ui/native_theme",
     "//url",
   ]

mojo/services/html_viewer/DEPS

@@ -14,5 +14,6 @@ include_rules = [
   "+third_party/skia/include",
   "+ui/base",
   "+ui/events",
+  "+ui/gfx/geometry",
   "+ui/native_theme",
 ]

mojo/services/html_viewer/html_document.cc

@@ -41,6 +41,7 @@
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkDevice.h"
+#include "ui/gfx/geometry/dip_util.h"
 
 using mojo::AxProvider;
 using mojo::Rect;
@@ -135,10 +136,7 @@ void HTMLDocument::OnEmbed(
   root_ = root;
   embedder_service_provider_ = exposed_services.Pass();
   navigator_host_.set_service_provider(embedder_service_provider_.get());
-
-  blink::WebSize root_size(root_->bounds().width, root_->bounds().height);
-  web_view_->resize(root_size);
-  web_layer_tree_view_impl_->setViewportSize(root_size);
+  UpdateWebviewSizeFromViewSize();
   web_layer_tree_view_impl_->set_view(root_);
   root_->AddObserver(this);
 }
@@ -174,6 +172,16 @@ void HTMLDocument::Load(URLResponsePtr response) {
   web_view_->mainFrame()->loadRequest(web_request);
 }
 
+void HTMLDocument::UpdateWebviewSizeFromViewSize() {
+  web_view_->setDeviceScaleFactor(root_->viewport_metrics().device_pixel_ratio);
+  const gfx::Size size_in_pixels(root_->bounds().width, root_->bounds().height);
+  const gfx::Size size_in_dips = gfx::ConvertSizeToDIP(
+      root_->viewport_metrics().device_pixel_ratio, size_in_pixels);
+  web_view_->resize(
+      blink::WebSize(size_in_dips.width(), size_in_dips.height()));
+  web_layer_tree_view_impl_->setViewportSize(size_in_pixels);
+}
+
 blink::WebStorageNamespace* HTMLDocument::createSessionStorageNamespace() {
   return new WebStorageNamespaceImpl();
 }
@@ -303,8 +311,7 @@ void HTMLDocument::OnViewBoundsChanged(View* view,
                                        const Rect& old_bounds,
                                        const Rect& new_bounds) {
   DCHECK_EQ(view, root_);
-  web_view_->resize(
-      blink::WebSize(view->bounds().width, view->bounds().height));
+  UpdateWebviewSizeFromViewSize();
 }
 
 void HTMLDocument::OnViewDestroyed(View* view) {

mojo/services/html_viewer/html_document.h

@@ -69,6 +69,10 @@ class HTMLDocument : public blink::WebViewClient,
   virtual ~HTMLDocument();
 
  private:
+  // Updates the size and scale factor of the webview and related classes from
+  // |root_|.
+  void UpdateWebviewSizeFromViewSize();
+
   // WebViewClient methods:
   virtual blink::WebStorageNamespace* createSessionStorageNamespace();