Support browser side thumbnailing for GPU composited pages on Windows.

content/content_browser.gypi

Index: content/content_browser.gypi
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 7c4e45d7ea2d0e746cc7474136b279e88c652335..9d962f11f498dfdaea4e19b5b369b4ecebfbebd0 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -554,6 +554,7 @@
     'browser/renderer_host/render_widget_host_view_mac_editcommand_helper.mm',
     'browser/renderer_host/render_widget_host_view_win.cc',
     'browser/renderer_host/render_widget_host_view_win.h',
+    'browser/renderer_host/render_widget_host_win.cc',
     'browser/renderer_host/resource_dispatcher_host.cc',
     'browser/renderer_host/resource_dispatcher_host.h',
     'browser/renderer_host/resource_dispatcher_host_request_info.cc',
@@ -821,6 +822,7 @@
         ['exclude', '^browser/renderer_host/render_widget_host.h'],
         ['exclude', '^browser/renderer_host/render_widget_host_view_win.cc'],
         ['exclude', '^browser/renderer_host/render_widget_host_view_win.h'],
+        ['exclude', '^browser/renderer_host/render_widget_host_win.cc'],
         ['exclude', '^browser/renderer_host/render_message_filter_win.cc'],
       ],
     }, {