harmony: fix sizing on webusb chooser dialog

chrome/browser/ui/views/device_chooser_content_view.cc

Index: chrome/browser/ui/views/device_chooser_content_view.cc
diff --git a/chrome/browser/ui/views/device_chooser_content_view.cc b/chrome/browser/ui/views/device_chooser_content_view.cc
index 6946d8709d805ee8d7be79dbef4f24053b9f9423..c37bf3663c9a8caefa9d86dbcf4c1a24a380e908 100644
--- a/chrome/browser/ui/views/device_chooser_content_view.cc
+++ b/chrome/browser/ui/views/device_chooser_content_view.cc
@@ -7,6 +7,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/numerics/safe_conversions.h"
 #include "chrome/app/vector_icons/vector_icons.h"
+#include "chrome/browser/ui/views/harmony/layout_delegate.h"
 #include "chrome/grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -110,6 +111,16 @@ void DeviceChooserContentView::Layout() {
   views::View::Layout();
 }
 
+gfx::Size DeviceChooserContentView::GetPreferredSize() const {
+  constexpr int kHeight = 320;
+  constexpr int kDefaultWidth = 402;
+  int width = LayoutDelegate::Get()->GetDialogPreferredWidth(
+      LayoutDelegate::DialogWidth::MEDIUM);
+  if (!width)
+    width = kDefaultWidth;
+  return gfx::Size(width, kHeight);
+}
+
 int DeviceChooserContentView::RowCount() {
   // When there are no devices, the table contains a message saying there
   // are no devices, so the number of rows is always at least 1.