Flag and adapter class for software compositing.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 3c9e7856b210e443f9fd709b74dfd9be106912d0..3d05849ff67df16a9654c4a2238141f5bdb5fd81 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -69,6 +69,7 @@
 #include "content/renderer/external_popup_menu.h"
 #include "content/renderer/geolocation_dispatcher.h"
 #include "content/renderer/gpu/compositor_thread.h"
+#include "content/renderer/gpu/compositor_output_canvas_3d_to_2d_adapter.h"
 #include "content/renderer/gpu/compositor_output_surface.h"
 #include "content/renderer/idle_user_detector.h"
 #include "content/renderer/input_tag_speech_dispatcher.h"
@@ -1804,9 +1805,6 @@ WebStorageNamespace* RenderViewImpl::createSessionStorageNamespace(
 }
 
 WebKit::WebCompositorOutputSurface* RenderViewImpl::createOutputSurface() {
-  // TODO(aelias): if force-software-mode is on, create an output surface
-  // without a 3D context.
-
   // Explicitly disable antialiasing for the compositor. As of the time of
   // this writing, the only platform that supported antialiasing for the
   // compositor was Mac OS X, because the on-screen OpenGL context creation
@@ -1824,7 +1822,15 @@ WebKit::WebCompositorOutputSurface* RenderViewImpl::createOutputSurface() {
   if (!context)
     return NULL;
 
-  return new CompositorOutputSurface(routing_id(), context);
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kForceSoftwareCompositing)) {
+      // Until we get a software-based delegating renderer, use this stopgap
+      // adapter class to present the software renderer output using a 3d
+      // context.
+      return new CompositorOutputSurface(routing_id(), NULL,
+          new CompositorOutputCanvas3DTo2DAdapter(context));
+  } else
+      return new CompositorOutputSurface(routing_id(), context, NULL);
 }
 
 void RenderViewImpl::didAddMessageToConsole(