Mac Support for drag-and-drop tests that start dragging via mouse simulation.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 09357b1b067ef661ec73a093d98db6402a101705..4925481da2dab94f2703706e00aae1213831e90b 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -240,6 +240,9 @@ std::vector<DropData::Metadata> DropDataToMetaData(const DropData& drop_data) {
   return metadata;
 }
 
+base::LazyInstance<RenderWidgetHostImpl::DragStartCallback>::Leaky
+    g_drag_start_callback_for_testing = LAZY_INSTANCE_INITIALIZER;
+
 }  // namespace
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -1502,8 +1505,14 @@ void RenderWidgetHostImpl::OnStartDragging(
     const SkBitmap& bitmap,
     const gfx::Vector2d& bitmap_offset_in_dip,
     const DragEventSourceInfo& event_info) {
+  bool drag_start_handled_by_test = false;
+  if (!g_drag_start_callback_for_testing.Get().is_null()) {
+    drag_start_handled_by_test = g_drag_start_callback_for_testing.Get().Run(
+        drop_data, drag_operations_mask);
+  }
+
   RenderViewHostDelegateView* view = delegate_->GetDelegateView();
-  if (!view) {
+  if (!view || drag_start_handled_by_test) {
     // Need to clear drag and drop state in blink.
     DragSourceSystemDragEnded();
     return;
@@ -2530,4 +2539,14 @@ void RenderWidgetHostImpl::GrantFileAccessFromDropData(DropData* drop_data) {
   }
 }
 
+// static
+void RenderWidgetHostImpl::RegisterDragStartCallbackForTesting(
+    DragStartCallback callback) {
+  // Prevent attempts to register more than one callback.
+  DCHECK(callback.is_null() ||
+         g_drag_start_callback_for_testing.Get().is_null());
+
+  g_drag_start_callback_for_testing.Get() = std::move(callback);
+}
+
 }  // namespace content