Re-implement the screensaver to use WebView instead of ExtensionDialogHost.

ash/ash.gyp

Index: ash/ash.gyp
diff --git a/ash/ash.gyp b/ash/ash.gyp
index 47e6b8ae91880cdf305364cda93192ae6c09c34e..37f28da086f254149c1d67f76609c2957f8c6bee 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -18,6 +18,9 @@
         '../base/base.gyp:base_i18n',
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         '../build/temp_gyp/googleurl.gyp:googleurl',
+        '../content/content.gyp:content',
+        '../content/content.gyp:content_browser',
+        '../ipc/ipc.gyp:ipc',
         '../net/net.gyp:net',
         '../skia/skia.gyp:skia',
         '../third_party/icu/icu.gyp:icui18n',
@@ -111,6 +114,8 @@
         'monitor/secondary_monitor_view.h',
         'screen_ash.cc',
         'screen_ash.h',
+        'screensaver/screensaver_view.cc',
+        'screensaver/screensaver_view.h',
         'screenshot_delegate.h',
         'shell.cc',
         'shell.h',
@@ -323,6 +328,8 @@
         '../base/base.gyp:base',
         '../base/base.gyp:test_support_base',
         '../chrome/chrome_resources.gyp:packed_resources',
+        '../content/content.gyp:content_browser',
+        '../content/content.gyp:test_support_content',
         '../build/temp_gyp/googleurl.gyp:googleurl',
         '../skia/skia.gyp:skia',
         '../testing/gtest.gyp:gtest',
@@ -337,6 +344,7 @@
         '../ui/ui.gyp:ui_resources',
         '../ui/ui.gyp:ui_resources_standard',
         '../ui/views/views.gyp:views',
+        '../ui/views/views.gyp:test_support_views',
         'ash',
       ],
       'sources': [
@@ -356,6 +364,7 @@
         'launcher/launcher_unittest.cc',
         'launcher/launcher_view_unittest.cc',
         'monitor/multi_monitor_manager_unittest.cc',
+        'screensaver/screensaver_view_unittest.cc',
         'shell_unittest.cc',
         'test/ash_test_base.cc',
         'test/ash_test_base.h',
@@ -457,6 +466,7 @@
         '../ui/ui.gyp:ui_resources_standard',
         '../ui/views/views.gyp:views',
         '../ui/views/views.gyp:views_examples_lib',
+        '../ui/views/views.gyp:test_support_views',
         'ash',
       ],
       'sources': [