[UnifiedPDF] Revert back to the fixed-size plugin

https://bugs.webkit.org/show_bug.cgi?id=262831
rdar://116609170

Reviewed by Tim Horton and Chris Dumez.

Undo some of 268697@main so that the UnifiedPDFPlugin once again is a fixed size; in future, it will
scroll internally as the PDFPlugin does.

So simplify the style in `PluginDocumentParser::createStyleElement()` to have the html, body and
embed all be width and height 100%, and make the document non-scrollable. Remove
`pluginFillsViewport()`. Resize the layers when we get `geometryDidChange()`.

Also ensure that the layer tree is updated when the plugin loads the PDF via a call to
`invalidateStyleAndLayerComposition()` in `PluginView::manualLoadDidFinishLoading()`.

Fix a spelling error in "udpateLayerHierarchy".

* Source/WebCore/html/PluginDocument.cpp:
(WebCore::PluginDocumentParser::createStyleElement):
* Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.h:
(WebKit::PDFPluginBase::pluginFillsViewport const): Deleted.
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm:
(WebKit::UnifiedPDFPlugin::installPDFDocument):
(WebKit::UnifiedPDFPlugin::updateLayerHierarchy):
(WebKit::UnifiedPDFPlugin::deviceScaleFactor const):
(WebKit::UnifiedPDFPlugin::geometryDidChange):
(WebKit::UnifiedPDFPlugin::sizeToFitContents): Deleted.
(WebKit::UnifiedPDFPlugin::udpateLayerHierarchy): Deleted.
* Source/WebKit/WebProcess/Plugins/PluginView.cpp:
(WebKit::PluginView::PluginView):
(WebKit::PluginView::manualLoadDidFinishLoading):
(WebKit::PluginView::updateDocumentForPluginSizingBehavior): Deleted.

Canonical link: https://commits.webkit.org/269048@main

Source/WebCore/html/PluginDocument.cpp

@@ -75,13 +75,7 @@ Ref<HTMLStyleElement> PluginDocumentParser::createStyleElement(Document& documen
 {
     auto styleElement = HTMLStyleElement::create(document);
 
-    constexpr auto styleSheetContents = R"CONTENTS(
-html.plugin-fills-viewport, html.plugin-fills-viewport body, html.plugin-fills-viewport embed { width: 100%; height: 100%; }
-html.plugin-fills-viewport body { overflow: hidden; }
-body { margin: 0; }
-embed { width: 100%; }
-)CONTENTS"_s;
-
+    constexpr auto styleSheetContents = "html, body, embed { width: 100%; height: 100%; }\nbody { margin: 0; overflow: hidden; }\n"_s;
 #if PLATFORM(IOS_FAMILY)
     constexpr auto bodyBackgroundColorStyle = "body { background-color: rgb(217, 224, 233) }"_s;
 #else

Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.h

@@ -78,8 +78,6 @@ class PDFPluginBase : public ThreadSafeRefCounted<PDFPluginBase> {
     virtual PlatformLayer* platformLayer() const { return nullptr; }
     virtual WebCore::GraphicsLayer* graphicsLayer() const { return nullptr; }
 
-    virtual bool pluginFillsViewport() const { return true; }
-
     virtual void setView(PluginView&);
 
     virtual void willDetachRenderer() { }

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h

@@ -46,8 +46,6 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
     WebCore::PluginLayerHostingStrategy layerHostingStrategy() const override { return WebCore::PluginLayerHostingStrategy::GraphicsLayer; }
     WebCore::GraphicsLayer* graphicsLayer() const override;
 
-    bool pluginFillsViewport() const override { return false; }
-
     void teardown() override;
 
     void createPDFDocument() override;
@@ -87,9 +85,9 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
 
     // GraphicsLayerClient
     void paintContents(const WebCore::GraphicsLayer*, WebCore::GraphicsContext&, const WebCore::FloatRect&, OptionSet<WebCore::GraphicsLayerPaintBehavior>) override;
+    float deviceScaleFactor() const override;
 
-    void sizeToFitContents();
-    void udpateLayerHierarchy();
+    void updateLayerHierarchy();
 
     RefPtr<WebCore::GraphicsLayer> createGraphicsLayer(const String& name, GraphicsLayer::Type);
 

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm

@@ -86,18 +86,7 @@
         return;
 
     m_documentLayout.updateLayout(size());
-    udpateLayerHierarchy();
-    sizeToFitContents();
-
-    m_contentsLayer->setNeedsDisplay();
-}
-
-void UnifiedPDFPlugin::sizeToFitContents()
-{
-    auto contentsSize = expandedIntSize(m_documentLayout.scaledContentsSize());
-
-    auto& pluginElement = m_view->pluginElement();
-    pluginElement.setInlineStyleProperty(CSSPropertyHeight, contentsSize.height(), CSSUnitType::CSS_PX);
+    updateLayerHierarchy();
 }
 
 RefPtr<GraphicsLayer> UnifiedPDFPlugin::createGraphicsLayer(const String& name, GraphicsLayer::Type layerType)
@@ -113,17 +102,24 @@
     return graphicsLayer;
 }
 
-void UnifiedPDFPlugin::udpateLayerHierarchy()
+void UnifiedPDFPlugin::updateLayerHierarchy()
 {
-    m_rootLayer = createGraphicsLayer("UnifiedPDFPlugin root"_s, GraphicsLayer::Type::Normal);
-    m_rootLayer->setAnchorPoint({ });
+    if (!m_rootLayer) {
+        auto rootLayer = createGraphicsLayer("UnifiedPDFPlugin root"_s, GraphicsLayer::Type::Normal);
+        m_rootLayer = rootLayer.copyRef();
+        rootLayer->setAnchorPoint({ });
+    }
 
-    m_contentsLayer = createGraphicsLayer("UnifiedPDFPlugin contents"_s, GraphicsLayer::Type::Normal);
-    m_contentsLayer->setAnchorPoint({ });
-    m_contentsLayer->setSize(size());
-    m_contentsLayer->setDrawsContent(true);
+    if (!m_contentsLayer) {
+        auto contentsLayer = createGraphicsLayer("UnifiedPDFPlugin contents"_s, GraphicsLayer::Type::Normal);
+        m_contentsLayer = contentsLayer.copyRef();
+        contentsLayer->setAnchorPoint({ });
+        contentsLayer->setDrawsContent(true);
+        m_rootLayer->addChild(*contentsLayer);
+    }
 
-    m_rootLayer->addChild(*m_contentsLayer);
+    m_contentsLayer->setSize(size());
+    m_contentsLayer->setNeedsDisplay();
 }
 
 void UnifiedPDFPlugin::paintContents(const GraphicsLayer* layer, GraphicsContext& context, const FloatRect& clipRect, OptionSet<GraphicsLayerPaintBehavior>)
@@ -188,6 +184,16 @@
     return 1;
 }
 
+float UnifiedPDFPlugin::deviceScaleFactor() const
+{
+    RefPtr frame = m_view->frame();
+    auto* page = frame->page();
+    if (!page)
+        return 1;
+
+    return page->deviceScaleFactor();
+}
+
 void UnifiedPDFPlugin::geometryDidChange(const IntSize& pluginSize, const AffineTransform& pluginToRootViewTransform)
 {
     if (size() == pluginSize)
@@ -196,7 +202,7 @@
     PDFPluginBase::geometryDidChange(pluginSize, pluginToRootViewTransform);
 
     m_documentLayout.updateLayout(size());
-    sizeToFitContents();
+    updateLayerHierarchy();
 }
 
 RetainPtr<PDFDocument> UnifiedPDFPlugin::pdfDocumentForPrinting() const

Source/WebKit/WebProcess/Plugins/PluginView.cpp

@@ -239,7 +239,6 @@ PluginView::PluginView(HTMLPlugInElement& element, const URL& mainResourceURL, c
     , m_pendingResourceRequestTimer(RunLoop::main(), this, &PluginView::pendingResourceRequestTimerFired)
 {
     m_webPage->addPluginView(*this);
-    updateDocumentForPluginSizingBehavior();
 }
 
 PluginView::~PluginView()
@@ -256,16 +255,6 @@ LocalFrame* PluginView::frame() const
     return m_pluginElement->document().frame();
 }
 
-void PluginView::updateDocumentForPluginSizingBehavior()
-{
-    if (!m_plugin->pluginFillsViewport())
-        return;
-
-    RefPtr documentElement = m_pluginElement->document().documentElement();
-    // The styles in PluginDocumentParser are constructed to respond to this class.
-    documentElement->setAttributeWithoutSynchronization(HTMLNames::classAttr, "plugin-fills-viewport"_s);
-}
-
 void PluginView::manualLoadDidReceiveResponse(const ResourceResponse& response)
 {
     if (!m_isInitialized) {
@@ -298,6 +287,11 @@ void PluginView::manualLoadDidFinishLoading()
     }
 
     m_plugin->streamDidFinishLoading();
+
+    if (layerHostingStrategy() != PluginLayerHostingStrategy::None) {
+        // This ensures that we update RenderLayers and compositing when the result of RenderEmbeddedObject::requiresLayer() changes.
+        Ref { m_pluginElement }->invalidateStyleAndLayerComposition();
+    }
 }
 
 void PluginView::manualLoadDidFail()
@@ -384,7 +378,7 @@ void PluginView::initializePlugin()
 #if PLATFORM(COCOA)
     if (m_plugin->isComposited() && frame()) {
         frame()->view()->enterCompositingMode();
-        m_pluginElement->invalidateStyleAndLayerComposition();
+        Ref { m_pluginElement }->invalidateStyleAndLayerComposition();
     }
     m_plugin->visibilityDidChange(isVisible());
 #endif