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

cef_paths2.gypi

@@ -91,6 +91,7 @@
       'tests/cefclient/res/domaccess.html',
       'tests/cefclient/res/localstorage.html',
       'tests/cefclient/res/logo.png',
+      'tests/cefclient/res/osr_test.html',
       'tests/cefclient/res/other_tests.html',
       'tests/cefclient/res/performance.html',
       'tests/cefclient/res/performance2.html',
@@ -103,6 +104,8 @@
       'tests/cefclient/cefclient.h',
       'tests/cefclient/binding_test.cpp',
       'tests/cefclient/binding_test.h',
+      'tests/cefclient/bytes_write_handler.cpp',
+      'tests/cefclient/bytes_write_handler.h',
       'tests/cefclient/client_app.cpp',
       'tests/cefclient/client_app.h',
       'tests/cefclient/client_app_delegates.cpp',
@@ -116,6 +119,9 @@
       'tests/cefclient/dialog_test.h',
       'tests/cefclient/dom_test.cpp',
       'tests/cefclient/dom_test.h',
+      'tests/cefclient/dragdrop_events.h',
+      'tests/cefclient/osrenderer.h',
+      'tests/cefclient/osrenderer.cpp',
       'tests/cefclient/performance_test.cpp',
       'tests/cefclient/performance_test.h',
       'tests/cefclient/performance_test_setup.h',
@@ -133,6 +139,10 @@
     'cefclient_sources_win': [
       'tests/cefclient/cefclient.exe.manifest',
       'tests/cefclient/cefclient.rc',
+      'tests/cefclient/cefclient_osr_dragdrop_win.h',
+      'tests/cefclient/cefclient_osr_dragdrop_win.cpp',
+      'tests/cefclient/cefclient_osr_widget_win.h',
+      'tests/cefclient/cefclient_osr_widget_win.cpp',
       'tests/cefclient/cefclient_win.cpp',
       'tests/cefclient/client_handler_win.cpp',
       'tests/cefclient/resource.h',
@@ -143,6 +153,8 @@
     ],
     'cefclient_sources_mac': [
       'tests/cefclient/cefclient_mac.mm',
+      'tests/cefclient/cefclient_osr_widget_mac.h',
+      'tests/cefclient/cefclient_osr_widget_mac.mm',
       'tests/cefclient/client_handler_mac.mm',
       'tests/cefclient/resource_util_mac.mm',
       'tests/cefclient/resource_util_posix.cpp',
@@ -191,6 +203,8 @@
     ],
     'cefclient_sources_linux': [
       'tests/cefclient/cefclient_gtk.cpp',
+      'tests/cefclient/cefclient_osr_widget_gtk.h',
+      'tests/cefclient/cefclient_osr_widget_gtk.cpp',
       'tests/cefclient/client_handler_gtk.cpp',
       'tests/cefclient/resource_util_linux.cpp',
       'tests/cefclient/resource_util_posix.cpp',