Add mssa configs for vulkan, and simple bug fix

BUG=skia:5127
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251473002

Review-Url: https://codereview.chromium.org/2251473002
diff --git a/src/gpu/vk/GrVkUtil.cpp b/src/gpu/vk/GrVkUtil.cpp
index ffbad25..e0d5daf 100644
--- a/src/gpu/vk/GrVkUtil.cpp
+++ b/src/gpu/vk/GrVkUtil.cpp
@@ -231,19 +231,19 @@
             *vkSamples = VK_SAMPLE_COUNT_2_BIT;
             return true;
         case 4:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_4_BIT;
             return true;
         case 8:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_8_BIT;
             return true;
         case 16:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_16_BIT;
             return true;
         case 32:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_32_BIT;
             return true;
         case 64:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_64_BIT;
             return true;
         default:
             return false;
diff --git a/tools/flags/SkCommonFlagsConfig.cpp b/tools/flags/SkCommonFlagsConfig.cpp
index 215fbdb..e25ccd3 100644
--- a/tools/flags/SkCommonFlagsConfig.cpp
+++ b/tools/flags/SkCommonFlagsConfig.cpp
@@ -127,6 +127,8 @@
 #ifdef SK_VULKAN
     "\tvk        \t= gpu(api=vulkan)\n"
     "\tvksrgb    \t= gpu(api=vulkan,color=srgb)\n"
+    "\tvkmsaa4   \t= gpu(api=gl,samples=4)\n"
+    "\tvkmsaa16  \t= gpu(api=gl,samples=16)\n"
 #endif
 #endif
     ;
@@ -179,8 +181,10 @@
     , { "mesa", "gpu", "api=mesa" }
 #endif
 #ifdef SK_VULKAN
-    , { "vk", "gpu", "api=vulkan" }
-    , { "vksrgb", "gpu", "api=vulkan,color=srgb" }
+    , { "vk",       "gpu", "api=vulkan" }
+    , { "vksrgb",   "gpu", "api=vulkan,color=srgb" }
+    , { "vkmsaa4",  "gpu", "api=vulkan,samples=4" }
+    , { "vkmsaa16", "gpu", "api=vulkan,samples=16" }
 #endif
 
 #else