Implement off-screen rendering support using delegated rendering (issue #1257).

This implementation supports both GPU compositing and software compositing (used when GPU is not supported or when passing `--disable-gpu --disable-gpu-compositing` command-line flags). GPU-accelerated features (WebGL and 3D CSS) that did not work with the previous off-screen rendering implementation do work with this implementation when GPU support is available.

Rendering now operates on a per-frame basis. The frame rate is configurable via CefBrowserSettings.windowless_frame_rate up to a maximum of 60fps (potentially limited by how fast the system can generate new frames). CEF generates a bitmap from the compositor backing and passes it to CefRenderHandler::OnPaint.

The previous CefRenderHandler/CefBrowserHost API for off-screen rendering has been restored mostly as-is with some minor changes:

- CefBrowserHost::Invalidate no longer accepts a CefRect region argument. Instead of invalidating a specific region it now triggers generation of a new frame.
- The |dirtyRects| argument to CefRenderHandler::OnPaint will now always be a single CefRect representing the whole view (frame) size. Previously, invalidated regions were listed separately.
- Linux: CefBrowserHost::SendKeyEvent now expects X11 event information instead of GTK event information. See cefclient for an example of converting GTK events to the necessary format.
- Sizes passed to the CefRenderHandler OnPaint and OnPopupSize methods are now already DPI scaled. Previously, the client had to perform DPI scaling.
- Includes drag&drop implementation from issue #1032.
- Includes unit test fixes from issue #1245.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@1751 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser/menu_creator_runner_mac.mm

@@ -61,9 +61,33 @@ bool CefMenuCreatorRunnerMac::RunContextMenu(CefMenuCreator* manager) {
     base::mac::ScopedSendingEvent sendingEventScoper;
 
     // Show the menu. Blocks until the menu is dismissed.
-    [NSMenu popUpContextMenu:[menu_controller_ menu]
-                   withEvent:clickEvent
-                     forView:parent_view];
+    if (manager->browser()->IsWindowless()) {
+      // Showing the menu in OSR is pretty much self contained, only using
+      // the initialized menu_controller_ in this function, and the scoped
+      // variables in this block.
+      int screenX = 0, screenY = 0;
+      CefRefPtr<CefRenderHandler> handler =
+          manager->browser()->GetClient()->GetRenderHandler();
+      if (!handler->GetScreenPoint(manager->browser(),
+                                   manager->params().x, manager->params().y,
+                                   screenX, screenY)) {
+        return false;
+      }
+
+      // Don't show the menu unless there is a parent native window to tie it to
+      if (!manager->browser()->GetWindowHandle())
+        return false;
+
+      NSPoint screen_position =
+          NSPointFromCGPoint(gfx::Point(screenX, screenY).ToCGPoint());
+      [[menu_controller_ menu] popUpMenuPositioningItem:nil
+                                             atLocation:screen_position
+                                                 inView:nil];
+    } else {
+      [NSMenu popUpContextMenu:[menu_controller_ menu]
+                     withEvent:clickEvent
+                       forView:parent_view];
+    }
   }
 
   return true;