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

third_party/WebKit/Source/web/PopupMenuImpl.cpp

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "web/PopupMenuImpl.h"
 
 #include "core/HTMLNames.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/dom/ElementTraversal.h"
@@ skipping 276 matching lines @@
             addOption(context, toHTMLOptionElement(child));
         else if (isHTMLOptGroupElement(child))
             addOptGroup(context, toHTMLOptGroupElement(child));
         else if (isHTMLHRElement(child))
             addSeparator(context, toHTMLHRElement(child));
     }
     context.finishGroupIfNecessary();
     PagePopupClient::addString("],\n", data);
 
     addProperty("anchorRectInScreen", anchorRectInScreen, data);
+    IntRect inScreen = m_chromeClient->viewportToScreen(IntRect(0, 0, 100, 0));
+    float scaleFactor = 100.f / inScreen.width();
+    addProperty("scaleFactor", scaleFactor, data);

[tkent, 2015/11/18 07:06:39]

I agree that we need to pass scale-factor in addition to zoom-factor.

After https://codereview.chromium.org/1454613002/, we should do the followings
for popups:
 - Update anchorRectInScreen to physical pixels
 - Adjust window.screen for scale-factor in pickerCommon.js adjustWindowRect()

     bool isRTL = !ownerStyle->isLeftToRightDirection();
     addProperty("isRTL", isRTL, data);
     addProperty("paddingStart", isRTL ? ownerElement.clientPaddingRight().toDouble() : ownerElement.clientPaddingLeft().toDouble(), data);
     PagePopupClient::addString("};\n", data);
     data->append(Platform::current()->loadResource("pickerCommon.js"));
     data->append(Platform::current()->loadResource("listPicker.js"));
     PagePopupClient::addString("</script></body>\n", data);
 }
 
 void PopupMenuImpl::addElementStyle(ItemIterationContext& context, HTMLElement& element)
@@ skipping 214 matching lines @@
 
 void PopupMenuImpl::disconnectClient()
 {
     m_ownerElement = nullptr;
     // Cannot be done during finalization, so instead done when the
     // layout object is destroyed and disconnected.
     dispose();
 }
 
 } // namespace blink