Initial checkin of accessibility extensions.

ui/accessibility/extensions/highcontrast/highcontrast.css

+/* Copyright (c) 2014 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file. */
+
+html[hc="a0"] {
+  -webkit-filter: url('#hc_extension_off');
+}
+html[hcx="0"] img[src*="jpg"],
+html[hcx="0"] img[src*="jpeg"],
+html[hcx="0"] svg image,
+html[hcx="0"] img.rg_i,
+html[hcx="0"] embed,
+html[hcx="0"] object,
+html[hcx="0"] video {
+  -webkit-filter: url('#hc_extension_off');
+}
+
+html[hc="a1"] {
+  -webkit-filter: url('#hc_extension_highcontrast');
+}
+html[hcx="1"] img[src*="jpg"],
+html[hcx="1"] img[src*="jpeg"],
+html[hcx="1"] img.rg_i,
+html[hcx="1"] svg image,
+html[hcx="1"] embed,
+html[hcx="1"] object,
+html[hcx="1"] video {
+  -webkit-filter: url('#hc_extension_highcontrast_back');
+}
+
+html[hc="a2"] {
+  -webkit-filter: url('#hc_extension_grayscale');
+}
+html[hcx="2"] img[src*="jpg"],
+html[hcx="2"] img[src*="jpeg"],
+html[hcx="2"] img.rg_i,
+html[hcx="2"] svg image,
+html[hcx="2"] embed,
+html[hcx="2"] object,
+html[hcx="2"] video {
+  -webkit-filter: url('#hc_extension_grayscale_back');
+}
+
+html[hc="a3"] {
+  -webkit-filter: url('#hc_extension_invert');
+}
+html[hcx="3"] img[src*="jpg"],
+html[hcx="3"] img[src*="jpeg"],
+html[hcx="3"] img.rg_i,
+html[hcx="3"] svg image,
+html[hcx="3"] embed,
+html[hcx="3"] object,
+html[hcx="3"] video {
+  -webkit-filter: url('#hc_extension_invert_back');
+}
+
+html[hc="a4"] {
+  -webkit-filter: url('#hc_extension_invert_grayscale');
+}
+html[hcx="4"] img[src*="jpg"],
+html[hcx="4"] img[src*="jpeg"],
+html[hcx="4"] img.rg_i,
+html[hcx="4"] svg image,
+html[hcx="4"] embed,
+html[hcx="4"] object,
+html[hcx="4"] video {
+  -webkit-filter: url('#hc_extension_invert_back');
+}
+
+html[hc="a5"] {
+  -webkit-filter: url('#hc_extension_yellow_on_black');
+}
+html[hcx="5"] img[src*="jpg"],
+html[hcx="5"] img[src*="jpeg"],
+html[hcx="5"] img.rg_i,
+html[hcx="5"] svg image,
+html[hcx="5"] embed,
+html[hcx="5"] object,
+html[hcx="5"] video {
+  -webkit-filter: url('#hc_extension_yellow_on_black_back');
+}