LibWeb: Add a PageClient callback for image context menu requests

When the user right-clicks on an image, you might want to show a
special context menu, separate from the regular link context menu.

This patch only implements enough of the functionality to get this
working in a single-process context.

Libraries/LibWeb/InProcessWebView.cpp

@@ -36,6 +36,7 @@
 #include <LibGUI/ScrollBar.h>
 #include <LibGUI/Window.h>
 #include <LibGfx/ImageDecoder.h>
+#include <LibGfx/ShareableBitmap.h>
 #include <LibJS/Runtime/Value.h>
 #include <LibWeb/DOM/Element.h>
 #include <LibWeb/DOM/ElementFactory.h>
@@ -171,6 +172,16 @@ void InProcessWebView::page_did_request_link_context_menu(const Gfx::IntPoint& c
         on_link_context_menu_request(url, screen_relative_rect().location().translated(to_widget_position(content_position)));
 }
 
+void InProcessWebView::page_did_request_image_context_menu(const Gfx::IntPoint& content_position, const URL& url, [[maybe_unused]] const String& target, [[maybe_unused]] unsigned modifiers, const Gfx::Bitmap* bitmap)
+{
+    if (!on_image_context_menu_request)
+        return;
+    Gfx::ShareableBitmap shareable_bitmap;
+    if (bitmap)
+        shareable_bitmap = Gfx::ShareableBitmap(*bitmap);
+    on_image_context_menu_request(url, screen_relative_rect().location().translated(to_widget_position(content_position)), shareable_bitmap);
+}
+
 void InProcessWebView::page_did_click_link(const URL& url, const String& target, unsigned modifiers)
 {
     if (on_link_click)

Libraries/LibWeb/InProcessWebView.h

@@ -94,6 +94,7 @@ private:
     virtual void page_did_request_cursor_change(Gfx::StandardCursor) override;
     virtual void page_did_request_context_menu(const Gfx::IntPoint&) override;
     virtual void page_did_request_link_context_menu(const Gfx::IntPoint&, const URL&, const String& target, unsigned modifiers) override;
+    virtual void page_did_request_image_context_menu(const Gfx::IntPoint&, const URL&, const String& target, unsigned modifiers, const Gfx::Bitmap*) override;
     virtual void page_did_click_link(const URL&, const String& target, unsigned modifiers) override;
     virtual void page_did_middle_click_link(const URL&, const String& target, unsigned modifiers) override;
     virtual void page_did_enter_tooltip_area(const Gfx::IntPoint&, const String&) override;

Libraries/LibWeb/Page/EventHandler.cpp

@@ -31,6 +31,7 @@
 #include <LibWeb/DOM/Text.h>
 #include <LibWeb/HTML/HTMLAnchorElement.h>
 #include <LibWeb/HTML/HTMLIFrameElement.h>
+#include <LibWeb/HTML/HTMLImageElement.h>
 #include <LibWeb/InProcessWebView.h>
 #include <LibWeb/Layout/LayoutDocument.h>
 #include <LibWeb/Page/EventHandler.h>
@@ -154,6 +155,13 @@ bool EventHandler::handle_mousedown(const Gfx::IntPoint& position, unsigned butt
     if (!layout_root())
         return true;
 
+    if (button == GUI::MouseButton::Right && is<HTML::HTMLImageElement>(*node)) {
+        auto& image_element = downcast<HTML::HTMLImageElement>(*node);
+        auto image_url = image_element.document().complete_url(image_element.src());
+        page_client.page_did_request_image_context_menu(m_frame.to_main_frame_position(position), image_url, "", modifiers, image_element.bitmap());
+        return true;
+    }
+
     if (RefPtr<HTML::HTMLAnchorElement> link = node->enclosing_link_element()) {
         auto href = link->href();
         auto url = document->complete_url(href);

Libraries/LibWeb/Page/Page.h

@@ -87,6 +87,7 @@ public:
     virtual void page_did_request_cursor_change(Gfx::StandardCursor) { }
     virtual void page_did_request_context_menu(const Gfx::IntPoint&) { }
     virtual void page_did_request_link_context_menu(const Gfx::IntPoint&, const URL&, [[maybe_unused]] const String& target, [[maybe_unused]] unsigned modifiers) { }
+    virtual void page_did_request_image_context_menu(const Gfx::IntPoint&, const URL&, [[maybe_unused]] const String& target, [[maybe_unused]] unsigned modifiers, const Gfx::Bitmap*) { }
     virtual void page_did_click_link(const URL&, [[maybe_unused]] const String& target, [[maybe_unused]] unsigned modifiers) { }
     virtual void page_did_middle_click_link(const URL&, [[maybe_unused]] const String& target, [[maybe_unused]] unsigned modifiers) { }
     virtual void page_did_enter_tooltip_area(const Gfx::IntPoint&, const String&) { }

Libraries/LibWeb/WebViewHooks.h

@@ -37,6 +37,7 @@ public:
     Function<void(const Gfx::IntPoint& screen_position)> on_context_menu_request;
     Function<void(const URL&, const String& target, unsigned modifiers)> on_link_click;
     Function<void(const URL&, const Gfx::IntPoint& screen_position)> on_link_context_menu_request;
+    Function<void(const URL&, const Gfx::IntPoint& screen_position, const Gfx::ShareableBitmap&)> on_image_context_menu_request;
     Function<void(const URL&, const String& target, unsigned modifiers)> on_link_middle_click;
     Function<void(const URL&)> on_link_hover;
     Function<void(const String&)> on_title_change;