Fix applying background color on RenderView

The RenderViewObserverQt_SetBackgroundColor message was sent with wrong
Routing ID.

This fix also cleans up RenderWidgetHostViewQt::UpdateBackgroundColor()
method.

Fixes: QTBUG-81781
Change-Id: Ida198fb061715d389859ace17e1f773db491c51d
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>

3 files changed, 49 insertions, 13 deletions

diff --git a/src/core/common/qt_messages.h b/src/core/common/qt_messages.h
index b99204b74..43f07c9a6 100644
--- a/src/core/common/qt_messages.h
+++ b/src/core/common/qt_messages.h
@@ -36,6 +36,9 @@ IPC_MESSAGE_ROUTED1(RenderViewObserverQt_FetchDocumentMarkup,
 IPC_MESSAGE_ROUTED1(RenderViewObserverQt_FetchDocumentInnerText,
                     uint64_t /* requestId */)
 
+IPC_MESSAGE_ROUTED1(RenderViewObserverQt_SetBackgroundColor,
+                    uint32_t /* color */)
+
 // User scripts messages
 IPC_MESSAGE_ROUTED1(RenderFrameObserverHelper_AddScript,
                     UserScriptData /* script */)
@@ -65,9 +68,6 @@ IPC_MESSAGE_ROUTED2(RenderViewObserverHostQt_DidFetchDocumentInnerText,
                     uint64_t /* requestId */,
                     base::string16 /* innerText */)
 
-IPC_MESSAGE_ROUTED1(RenderViewObserverQt_SetBackgroundColor,
-                    uint32_t /* color */)
-
 IPC_MESSAGE_ROUTED0(RenderViewObserverHostQt_DidFirstVisuallyNonEmptyLayout)
 
 //-----------------------------------------------------------------------------
diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp
index e9be587cf..7a5118837 100644
--- a/src/core/render_widget_host_view_qt.cpp
+++ b/src/core/render_widget_host_view_qt.cpp
@@ -48,6 +48,7 @@
 #include "touch_selection_controller_client_qt.h"
 #include "touch_selection_menu_controller.h"
 #include "type_conversion.h"
+#include "web_contents_adapter.h"
 #include "web_contents_adapter_client.h"
 #include "web_event_factory.h"
 
@@ -488,23 +489,20 @@ gfx::Rect RenderWidgetHostViewQt::GetViewBounds()
 
 void RenderWidgetHostViewQt::UpdateBackgroundColor()
 {
+    DCHECK(GetBackgroundColor());
+    SkColor color = *GetBackgroundColor();
+
+    m_delegate->setClearColor(toQt(color));
+
     if (m_enableViz) {
-        DCHECK(GetBackgroundColor());
-        SkColor color = *GetBackgroundColor();
         bool opaque = SkColorGetA(color) == SK_AlphaOPAQUE;
         m_rootLayer->SetFillsBoundsOpaquely(opaque);
         m_rootLayer->SetColor(color);
         m_uiCompositor->SetBackgroundColor(color);
-        m_delegate->setClearColor(toQt(color));
-        host()->Send(new RenderViewObserverQt_SetBackgroundColor(host()->GetRoutingID(), color));
-        return;
     }
 
-    auto color = GetBackgroundColor();
-    if (color) {
-        m_delegate->setClearColor(toQt(*color));
-        host()->Send(new RenderViewObserverQt_SetBackgroundColor(host()->GetRoutingID(), *color));
-    }
+    content::RenderViewHost *rvh = content::RenderViewHost::From(host());
+    host()->Send(new RenderViewObserverQt_SetBackgroundColor(rvh->GetRoutingID(), color));
 }
 
 // Return value indicates whether the mouse is locked successfully or not.
diff --git a/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp b/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
index 94b3f16c1..206e53a38 100644
--- a/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
+++ b/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
@@ -226,6 +226,7 @@ private Q_SLOTS:
 
     void customUserAgentInNewTab();
     void renderProcessCrashed();
+    void backgroundColor();
 
 private:
     static QPoint elementCenter(QWebEnginePage *page, const QString &id);
@@ -4368,6 +4369,43 @@ void tst_QWebEnginePage::renderProcessCrashed()
             status == QWebEnginePage::AbnormalTerminationStatus);
 }
 
+void tst_QWebEnginePage::backgroundColor()
+{
+    QWebEngineProfile profile;
+    QWebEngineView view;
+    QWebEnginePage *page = new QWebEnginePage(&profile, &view);
+
+    view.resize(640, 480);
+    view.show();
+    QPoint center(view.size().width() / 2, view.size().height() / 2);
+
+    QCOMPARE(page->backgroundColor(), Qt::white);
+    QTRY_COMPARE(view.grab().toImage().pixelColor(center), Qt::white);
+
+    page->setBackgroundColor(Qt::red);
+    view.setPage(page);
+
+    QCOMPARE(page->backgroundColor(), Qt::red);
+    QTRY_COMPARE(view.grab().toImage().pixelColor(center), Qt::red);
+
+    page->setHtml(QString("<html>"
+                          "<head><style>html, body { margin:0; padding:0; }</style></head>"
+                          "<body><div style=\"width:100%; height:10px; background-color:black\"/></body>"
+                          "</html>"));
+    QSignalSpy spyFinished(page, &QWebEnginePage::loadFinished);
+    QVERIFY(spyFinished.wait());
+    // Make sure the page is rendered and the test is not grabbing the color of the RenderWidgetHostViewQtDelegateWidget.
+    QTRY_COMPARE(view.grab().toImage().pixelColor(QPoint(5, 5)), Qt::black);
+
+    QCOMPARE(page->backgroundColor(), Qt::red);
+    QCOMPARE(view.grab().toImage().pixelColor(center), Qt::red);
+
+    page->setBackgroundColor(Qt::green);
+
+    QCOMPARE(page->backgroundColor(), Qt::green);
+    QTRY_COMPARE(view.grab().toImage().pixelColor(center), Qt::green);
+}
+
 static QByteArrayList params = {QByteArrayLiteral("--use-fake-device-for-media-stream")};
 W_QTEST_MAIN(tst_QWebEnginePage, params)