Support copying a partial rectangle region from the compositing surface on Aura and GTK.

content/browser/renderer_host/render_widget_host_view_gtk.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_gtk.h"
 
 // If this gets included after the gtk headers, then a bunch of compiler
 // errors happen because of a "#define Status int" in Xlib.h, which interacts
 // badly with net::URLRequestStatus::Status.
 #include "content/common/view_messages.h"
@@ skipping 1012 matching lines @@
 }
 
 BackingStore* RenderWidgetHostViewGtk::AllocBackingStore(
     const gfx::Size& size) {
   gint depth = gdk_visual_get_depth(gtk_widget_get_visual(view_.get()));
   return new BackingStoreGtk(host_, size,
                              ui::GetVisualFromGtkWidget(view_.get()),
                              depth);
 }
 
-// NOTE: |output| is initialized with the size of the view and |size| is
-// ignored on GTK.
+// NOTE: |output| is initialized with the size of |src_subrect|, and |dst_size|
+// is ignored on GTK.
 void RenderWidgetHostViewGtk::CopyFromCompositingSurface(
-    const gfx::Size& /* size */,
+    const gfx::Rect& src_subrect,
+    const gfx::Size& /* dst_size */,
     const base::Callback<void(bool)>& callback,
     skia::PlatformCanvas* output) {
   base::ScopedClosureRunner scoped_callback_runner(base::Bind(callback, false));
 
   const gfx::Rect bounds = GetViewBounds();
   XImage* image = XGetImage(ui::GetXDisplay(), ui::GetX11RootWindow(),
-                            bounds.x(), bounds.y(),
-                            bounds.width(), bounds.height(),
+                            bounds.x() + src_subrect.x(),
+                            bounds.y() + src_subrect.y(),
+                            src_subrect.width(),
+                            src_subrect.height(),
                             AllPlanes, ZPixmap);
   if (!image)
     return;
 
-  if (!output->initialize(bounds.width(), bounds.height(), true)) {
+  if (!output->initialize(src_subrect.width(), src_subrect.height(), true)) {
     XFree(image);
     return;
   }
 
   const SkBitmap& bitmap = output->getTopDevice()->accessBitmap(true);
   const size_t bitmap_size = bitmap.getSize();
   DCHECK_EQ(bitmap_size,
             static_cast<size_t>(image->height * image->bytes_per_line));
   unsigned char* pixels = static_cast<unsigned char*>(bitmap.getPixels());
   memcpy(pixels, image->data, bitmap_size);
@@ skipping 484 matching lines @@
             this));
   }
   BrowserAccessibilityGtk* root =
       browser_accessibility_manager_->GetRoot()->ToBrowserAccessibilityGtk();
 
   atk_object_set_role(root->GetAtkObject(), ATK_ROLE_HTML_CONTAINER);
   return root->GetAtkObject();
 }
 
 }  // namespace content