Remove popup overlay from MHTML when requested

third_party/WebKit/Source/web/WebFrameSerializer.cpp

Index: third_party/WebKit/Source/web/WebFrameSerializer.cpp
diff --git a/third_party/WebKit/Source/web/WebFrameSerializer.cpp b/third_party/WebKit/Source/web/WebFrameSerializer.cpp
index 9a266f1dce7545ba1fe7dfa7d3a26905d186d893..cd7c1c57e5ec8ac39183b52c368e28e187245bad 100644
--- a/third_party/WebKit/Source/web/WebFrameSerializer.cpp
+++ b/third_party/WebKit/Source/web/WebFrameSerializer.cpp
@@ -34,16 +34,20 @@
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/Frame.h"
+#include "core/frame/FrameHost.h"
 #include "core/frame/FrameSerializer.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/RemoteFrame.h"
+#include "core/frame/VisualViewport.h"
 #include "core/html/HTMLAllCollection.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLTableElement.h"
+#include "core/layout/LayoutBox.h"
 #include "core/loader/DocumentLoader.h"
+#include "core/page/Page.h"
 #include "platform/Histogram.h"
 #include "platform/SerializedResource.h"
 #include "platform/SharedBuffer.h"
@@ -77,6 +81,8 @@ namespace blink {
 
 namespace {
 
+const int kPopupOverlayZIndexThreshold = 50;
+
 class MHTMLFrameSerializerDelegate final : public FrameSerializer::Delegate {
   WTF_MAKE_NONCOPYABLE(MHTMLFrameSerializerDelegate);
 
@@ -92,6 +98,8 @@ class MHTMLFrameSerializerDelegate final : public FrameSerializer::Delegate {
   Vector<Attribute> getCustomAttributes(const Element&) override;
 
  private:
+  bool shouldIgnoreHiddenElement(const Element&);
+  bool shouldIgnorePopupOverlayElement(const Element&);
   void getCustomAttributesForImageElement(const HTMLImageElement&,
                                           Vector<Attribute>*);
   void getCustomAttributesForFormControlElement(const Element&,
@@ -105,6 +113,17 @@ MHTMLFrameSerializerDelegate::MHTMLFrameSerializerDelegate(
     : m_webDelegate(webDelegate) {}
 
 bool MHTMLFrameSerializerDelegate::shouldIgnoreElement(const Element& element) {
+  if (shouldIgnoreHiddenElement(element))
+    return true;
+  if (m_webDelegate.removePopupOverlay() &&
+      shouldIgnorePopupOverlayElement(element)) {
+    return true;
+  }
+  return false;
+}
+
+bool MHTMLFrameSerializerDelegate::shouldIgnoreHiddenElement(
+    const Element& element) {
   // Do not include elements that are are set to hidden without affecting layout
   // by the page. For those elements that are hidden by default, they will not
   // be excluded:
@@ -121,6 +140,29 @@ bool MHTMLFrameSerializerDelegate::shouldIgnoreElement(const Element& element) {
   return parent && !isHTMLHeadElement(parent);
 }
 
+bool MHTMLFrameSerializerDelegate::shouldIgnorePopupOverlayElement(
+    const Element& element) {
+  // The element should be visible.
+  LayoutBox* box = element.layoutBox();
+  if (!box || box->style()->display() == EDisplay::None)

[dcheng, 2017/01/19 18:24:55]

Note that an element styled with display:none won't have a LayoutObject (and
thus no LayoutBox), so the second part of the || is unnecessary.

[jianli, 2017/01/19 23:55:22]

Done.

+    return false;
+
+  // The bounding box of the element should contain center point of the

[Pete Williamson, 2017/01/19 18:08:28]

FYI - I have seen some popups in EM pages that do not cover the center of the
window. Would we be better without this check?

Example URLs with this behavior: 
http://www.ndtv.com/tv-schedule?pfrom=home-topnavigation2016
https://www.icicibank.com/

Although the dialog box does not cover the center, they grey out the rest of the
window, so if they do that with a transparent window, it might cover the center,
this might be a good test for your code.

[jianli, 2017/01/19 23:55:22]

The 1st one is covered while the 2nd one is not handled. Will investigate and
enhance the popup removal in future patch. For now, we're covering most common
and safe scenario: popup appearing at the center

+  // viewport.
+  LocalDOMWindow* window = element.document().domWindow();

[dcheng, 2017/01/19 18:24:55]

Nit: DCHECK instead of guarding with if, since we shouldn't be serializing
detached frames.

[jianli, 2017/01/19 23:55:22]

Done.

+  if (!window)
+    return false;
+  LayoutPoint centerPoint(window->innerWidth() / 2, window->innerHeight() / 2);
+  if (!box->frameRect().contains(centerPoint))
+    return false;
+
+  // The z-index should be greater than the threshold.
+  if (box->style()->zIndex() < kPopupOverlayZIndexThreshold)
+    return false;
+
+  return true;
+}
+
 bool MHTMLFrameSerializerDelegate::shouldIgnoreAttribute(
     const Element& element,
     const Attribute& attribute) {