Convert the sub-rectangle for GL functions from the views coordinate to the OpenGL coordinate.

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 814 matching lines @@
   if (!compositing_iosurface_.get() ||
       !compositing_iosurface_->HasIOSurface())
     return;
 
   float scale = ScaleFactor(cocoa_view_);
   gfx::Size dst_pixel_size = dst_size.Scale(scale);
   if (!output->initialize(
       dst_pixel_size.width(), dst_pixel_size.height(), true))
     return;
 
-  gfx::Rect src_pixel_subrect(src_subrect.origin().Scale(scale),
-                              src_subrect.size().Scale(scale));
+  // Convert |src_subrect| from the views coordinate (upper-left origin) into
+  // the OpenGL coordinate (lower-left origin).
+  gfx::Rect src_gl_subrect = src_subrect;
+  src_gl_subrect.set_y(GetViewBounds().height() - src_subrect.bottom());
+
+  gfx::Rect src_pixel_gl_subrect = src_gl_subrect.Scale(scale);
   const bool result = compositing_iosurface_->CopyTo(
-      src_pixel_subrect,
+      src_pixel_gl_subrect,
       dst_pixel_size,
       output->getTopDevice()->accessBitmap(true).getPixels());
   scoped_callback_runner.Release();
   callback.Run(result);
 }
 
 // Sets whether or not to accept first responder status.
 void RenderWidgetHostViewMac::SetTakesFocusOnlyOnMouseDown(bool flag) {
   [cocoa_view_ setTakesFocusOnlyOnMouseDown:flag];
 }
@@ skipping 2363 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end