Adding SwiftShader to the DEPS file

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index 35e4ea9227603d0e35309e78b452ec8c26066f81..2d2ff9e830238156679dd3802af6d4258647b8af 100644
--- a/DEPS
+++ b/DEPS
@@ -54,6 +54,10 @@ vars = {
   # and whatever else without interference from each other.
   'buildtools_revision': '60f7f9a8b421ebf9a46041dfa2ff11c0fe59c582',
   # Three lines of non-changing comments so that
+  # the commit queue can handle CLs rolling SwiftShader
+  # and whatever else without interference from each other.
+  'swiftshader_revision': '3e204de9bb74b5379b42b7eea5c4b898b2698d56',
+  # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
   'pdfium_revision': 'eea31b75a11215aa72a9845d47c38d2ce1edd4f7',
@@ -102,6 +106,7 @@ allowed_hosts = [
   'boringssl.googlesource.com',
   'pdfium.googlesource.com',
   'android.googlesource.com',
+  'swiftshader.googlesource.com',
 ]
 
 deps = {
@@ -252,6 +257,9 @@ deps = {
   'src/third_party/ced/src':
     Var('chromium_git') + '/external/github.com/google/compact_enc_det.git' + '@' + '45c3d4a3d7ee40adf271748f3c4177fa293800e1',
 
+  'src/third_party/swiftshader':
+   'https://swiftshader.googlesource.com/SwiftShader.git' + '@' +  Var('swiftshader_revision'),
+
   'src/third_party/cld_2/src':
     Var('chromium_git') + '/external/github.com/CLD2Owners/cld2.git' + '@' + '84b58a5d7690ebf05a91406f371ce00c3daf31c0',