Show PDF viewer in a guest view

This is the basic support of guest views, implemented based
on Chrome.
- Embed PDF as a child frame instead of navigating to its
extension WebUI. Keep the original URL (pointing to the file) to
extend functionality of PDF viewer with URL parameters.
- Make RenderWidgetHostInputEventRouter to work and modify most of
the event forwarding logic to use that. This way WebEngine supports
pages with multiple RenderWidgetHost and guest views can be
interactive with user input.

[ChangeLog] PDF files are opened as embedded objects, WebEngine
will not navigate the content away from the requested file to
present it. PDF viewer can accept URL parameters (e.g. to control
zooming or fitting to view). Also, PDF viewer is interactive
when displayed in a subframe.

Task-number: QTBUG-80463
Task-number: QTBUG-86152
Task-number: QTBUG-90712
Change-Id: Ib1591fbd9a594891cdeace8e9dae0d3cc21a9f8e
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/core/web_contents_adapter.cpp b/src/core/web_contents_adapter.cpp
index ee0c1fb3c..bfeab41a2 100644
--- a/src/core/web_contents_adapter.cpp
+++ b/src/core/web_contents_adapter.cpp
@@ -1547,7 +1547,15 @@ void WebContentsAdapter::startDragging(QObject *dragSource, const content::DropD
     QObject::disconnect(onDestroyed);
     if (dValid) {
         if (m_webContents) {
-            content::RenderViewHost *rvh = m_webContents->GetRenderViewHost();
+            // This is the quickest and (at the moment) the most safe solution to not break guest views when
+            // dropping data into them. We don't even try to support dropping into PDF input fields,
+            // since it's not working in Chrome right now.
+            content::WebContents *targetWebContents = m_webContents.get();
+            std::vector<content::WebContents *> innerWebContents = m_webContents->GetInnerWebContents();
+            if (!innerWebContents.empty())
+                targetWebContents = innerWebContents[0];
+
+            content::RenderViewHost *rvh = targetWebContents->GetRenderViewHost();
             if (rvh) {
                 rvh->GetWidget()->DragSourceEndedAt(gfx::PointF(m_lastDragClientPos.x(), m_lastDragClientPos.y()),
                                                     gfx::PointF(m_lastDragScreenPos.x(), m_lastDragScreenPos.y()),