Remove enable-software-compositing command-line flag.

content/shell/browser/webkit_test_controller.cc

Index: content/shell/browser/webkit_test_controller.cc
diff --git a/content/shell/browser/webkit_test_controller.cc b/content/shell/browser/webkit_test_controller.cc
index 4932e58887eb7da817545bc3334ca2b47fd27a75..5aca75aad6c976e09f3df4f7fddbf99c0e1ac81b 100644
--- a/content/shell/browser/webkit_test_controller.cc
+++ b/content/shell/browser/webkit_test_controller.cc
@@ -327,9 +327,6 @@ void WebKitTestController::OverrideWebkitPrefs(WebPreferences* prefs) {
   } else {
     ApplyLayoutTestDefaultPreferences(prefs);
     if (is_compositing_test_) {
-      CommandLine& command_line = *CommandLine::ForCurrentProcess();
-      if (!command_line.HasSwitch(switches::kEnableSoftwareCompositing))
-        prefs->accelerated_2d_canvas_enabled = true;

[piman, 2014/04/11 20:30:46]

I'm not sure that's right... this is used for layout tests, which have a
different set of flags that's set by default. It sounds like this would disable
accelerated canvas layout tests altogether?

IIRC that's where the virtual/softwarecompositing "virtual" test suite comes in.
See third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py

Maybe this can be keyed off --disable-gpu instead (which seems to be set as well
in that virtual test suite)?

       prefs->accelerated_compositing_for_video_enabled = true;
       prefs->mock_scrollbars_enabled = true;
     }