webview2: Add support for javascript injection

Allow javascript injection for various custom use cases.
For example, scrollbars and scrolling can be disabled via

gst-launch-1.0 webview2src location=https://gstreamer.freedesktop.org \
    javascript="document.querySelector('body').style.overflow='hidden'" ! ...

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6487>

subprojects/gst-plugins-bad/sys/webview2/gstwebview2object.cpp

@@ -119,7 +119,9 @@ GstGetActivationFactory (InterfaceType ** factory)
 class GstWebView2Item : public RuntimeClass<RuntimeClassFlags<ClassicCom>,
     FtmBase, IFrameArrivedHandler,
     ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler,
-    ICoreWebView2CreateCoreWebView2CompositionControllerCompletedHandler>
+    ICoreWebView2CreateCoreWebView2CompositionControllerCompletedHandler,
+    ICoreWebView2NavigationCompletedEventHandler,
+    ICoreWebView2ExecuteScriptCompletedHandler>
 {
 public:
   static LRESULT CALLBACK
@@ -238,6 +240,9 @@ public:
     hr = ctrl_->get_CoreWebView2 (&webview_);
     CHECK_HR_AND_RETURN (hr, get_CoreWebView2);
 
+    hr = webview_->add_NavigationCompleted (this, &navigation_compl_token_);
+    CHECK_HR_AND_RETURN (hr, get_CoreWebView2);
+
     ComPtr<ICoreWebView2_8> webview8;
     hr = webview_.As (&webview8);
     if (SUCCEEDED (hr))
@@ -251,6 +256,26 @@ public:
     return S_OK;
   }
 
+  IFACEMETHOD(Invoke) (HRESULT hr, LPCWSTR result_json)
+  {
+    GST_DEBUG_OBJECT (obj_, "Executing script result 0x%x", (guint) hr);
+
+    return S_OK;
+  }
+
+  IFACEMETHOD(Invoke) (ICoreWebView2 * sender,
+      ICoreWebView2NavigationCompletedEventArgs * arg)
+  {
+    GST_DEBUG_OBJECT (obj_, "Navigation completed");
+
+    if (!script_.empty ()) {
+      GST_DEBUG_OBJECT (obj_, "Executing script");
+      sender->ExecuteScript (script_.c_str (), this);
+    }
+
+    return S_OK;
+  }
+
   HRESULT
   startCapture ()
   {
@@ -367,11 +392,16 @@ public:
     comp_ = nullptr;
   }
 
-  HRESULT Navigate (LPCWSTR location)
+  HRESULT Navigate (LPCWSTR location, LPCWSTR script)
   {
     if (!webview_ || !location)
       return E_FAIL;
 
+    if (script)
+      script_ = script;
+    else
+      script_.clear ();
+
     return webview_->Navigate (location);
   }
 
@@ -503,6 +533,8 @@ private:
   ComPtr<ICoreWebView2Controller3> ctrl_;
   ComPtr<ICoreWebView2CompositionController > comp_ctrl_;
   ComPtr<ICoreWebView2 > webview_;
+  EventRegistrationToken navigation_compl_token_ = { };
+  std::wstring script_;
 
   ComPtr<IGraphicsCaptureItem> item_;
   SizeInt32 frame_size_ = { };
@@ -576,18 +608,23 @@ class UpdateLocationHandler : public RuntimeClass<RuntimeClassFlags<ClassicCom>,
 {
 public:
   STDMETHODIMP
-  RuntimeClassInitialize (GstWebView2Item * item, const std::string & location)
+  RuntimeClassInitialize (GstWebView2Item * item, const std::string & location,
+      const std::string & script)
   {
     item_ = item;
     location_wide_ = g_utf8_to_utf16 (location.c_str (),
         -1, nullptr, nullptr, nullptr);
+    if (!script.empty ()) {
+      script_wide_ = g_utf8_to_utf16 (script.c_str (),
+          -1, nullptr, nullptr, nullptr);
+    }
 
     return S_OK;
   }
 
   IFACEMETHOD(Invoke) (void)
   {
-    item_->Navigate ((LPCWSTR) location_wide_);
+    item_->Navigate ((LPCWSTR) location_wide_, (LPCWSTR) script_wide_);
     item_ = nullptr;
 
     return S_OK;
@@ -596,11 +633,13 @@ public:
   ~UpdateLocationHandler ()
   {
     g_free (location_wide_);
+    g_free (script_wide_);
   }
 
 private:
   ComPtr<GstWebView2Item> item_;
   gunichar2 *location_wide_ = nullptr;
+  gunichar2 *script_wide_ = nullptr;
 };
 
 class AsyncWaiter : public RuntimeClass<RuntimeClassFlags<ClassicCom>,
@@ -932,7 +971,7 @@ gst_webview2_object_new (GstD3D11Device * device)
 
 gboolean
 gst_webview2_object_set_location (GstWebView2Object * object,
-    const std::string & location)
+    const std::string & location, const std::string & script)
 {
   auto priv = object->priv;
   std::lock_guard < std::mutex > lk (priv->lock);
@@ -941,7 +980,7 @@ gst_webview2_object_set_location (GstWebView2Object * object,
 
   ComPtr < UpdateLocationHandler > handler;
   auto hr = MakeAndInitialize < UpdateLocationHandler > (&handler,
-      priv->item.Get (), location);
+      priv->item.Get (), location, script);
   if (FAILED (hr))
     return FALSE;
 

subprojects/gst-plugins-bad/sys/webview2/gstwebview2object.h

@@ -33,10 +33,12 @@ G_DECLARE_FINAL_TYPE (GstWebView2Object, gst_webview2_object,
 GstWebView2Object * gst_webview2_object_new          (GstD3D11Device * device);
 
 gboolean            gst_webview2_object_set_location (GstWebView2Object * client,
-                                                      const std::string & location);
+                                                      const std::string & location,
+                                                      const std::string & script);
 
 gboolean            gst_webview_object_update_size   (GstWebView2Object * client,
-                                                      guint width, guint height);
+                                                      guint width,
+                                                      guint height);
 
 void                gst_webview2_object_send_event   (GstWebView2Object * client,
                                                       GstEvent * event);

subprojects/gst-plugins-bad/sys/webview2/gstwebview2src.cpp

@@ -57,6 +57,7 @@ enum
   PROP_ADAPTER,
   PROP_LOCATION,
   PROP_PROCESSING_DEADLINE,
+  PROP_JAVASCRIPT,
 };
 
 #define DEFAULT_LOCATION "about:blank"
@@ -80,6 +81,7 @@ struct GstWebView2SrcPrivate
   gint adapter_index = DEFAULT_ADAPTER;
   std::string location = DEFAULT_LOCATION;
   GstClockTime processing_deadline = DEFAULT_PROCESSING_DEADLINE;
+  std::string script;
 };
 /* *INDENT-ON* */
 
@@ -138,7 +140,7 @@ gst_webview2_src_class_init (GstWebView2SrcClass * klass)
               G_PARAM_STATIC_STRINGS)));
 
   g_object_class_install_property (object_class, PROP_LOCATION,
-      g_param_spec_string ("location", "location",
+      g_param_spec_string ("location", "Location",
           "The URL to display",
           nullptr, (GParamFlags) (G_PARAM_READWRITE |
               G_PARAM_STATIC_STRINGS | GST_PARAM_MUTABLE_PLAYING)));
@@ -149,6 +151,12 @@ gst_webview2_src_class_init (GstWebView2SrcClass * klass)
           DEFAULT_PROCESSING_DEADLINE, (GParamFlags) (G_PARAM_READWRITE |
               G_PARAM_STATIC_STRINGS | GST_PARAM_MUTABLE_PLAYING)));
 
+  g_object_class_install_property (object_class, PROP_JAVASCRIPT,
+      g_param_spec_string ("javascript", "Javascript",
+          "Javascript to run on nevigation completed",
+          nullptr, (GParamFlags) (G_PARAM_READWRITE |
+              G_PARAM_STATIC_STRINGS | GST_PARAM_MUTABLE_PLAYING)));
+
   gst_element_class_set_static_metadata (element_class,
       "WebView2 Source", "Source/Video",
       "Creates a video stream rendered by WebView2",
@@ -208,8 +216,10 @@ gst_webview2_src_set_location (GstWebView2Src * self, const gchar * location)
   else
     priv->location = DEFAULT_LOCATION;
 
-  if (priv->object)
+  if (priv->object) {
-    gst_webview2_object_set_location (priv->object, priv->location);
+    gst_webview2_object_set_location (priv->object,
+        priv->location, priv->script);
+  }
 }
 
 static void
@@ -242,6 +252,20 @@ gst_webview2_src_set_property (GObject * object, guint prop_id,
       }
       break;
     }
+    case PROP_JAVASCRIPT:
+    {
+      auto script = g_value_get_string (value);
+      if (script)
+        priv->script = script;
+      else
+        priv->script.clear ();
+
+      if (priv->object) {
+        gst_webview2_object_set_location (priv->object, priv->location,
+            priv->script);
+      }
+      break;
+    }
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -266,6 +290,9 @@ gst_win32_video_src_get_property (GObject * object, guint prop_id,
     case PROP_PROCESSING_DEADLINE:
       g_value_set_uint64 (value, priv->processing_deadline);
       break;
+    case PROP_JAVASCRIPT:
+      g_value_set_string (value, priv->script.c_str ());
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -311,7 +338,7 @@ gst_webview2_src_start (GstBaseSrc * src)
     return FALSE;
   }
 
-  gst_webview2_object_set_location (priv->object, priv->location);
+  gst_webview2_object_set_location (priv->object, priv->location, priv->script);
 
   priv->last_frame_no = -1;