Fix 4444 on Vulkan devices who don't support RGBA_4444

src/gpu/vk/GrVkCaps.cpp

Index: src/gpu/vk/GrVkCaps.cpp
diff --git a/src/gpu/vk/GrVkCaps.cpp b/src/gpu/vk/GrVkCaps.cpp
index cf9f4f025e0a2a8d4b53a25a3a5f9ba711256803..0bd05f06a48707a13a28de0d69e54f3a081803c3 100644
--- a/src/gpu/vk/GrVkCaps.cpp
+++ b/src/gpu/vk/GrVkCaps.cpp
@@ -137,7 +137,12 @@ void GrVkCaps::initGLSLCaps(const VkPhysicalDeviceProperties& properties,
             glslCaps->fConfigTextureSwizzle[i] = GrSwizzle::RRRR();
             glslCaps->fConfigOutputSwizzle[i] = GrSwizzle::AAAA();
         } else {
-            glslCaps->fConfigTextureSwizzle[i] = GrSwizzle::RGBA();
+            if (kRGBA_4444_GrPixelConfig == config) {

[bsalomon, 2016/08/11 18:02:08]

Maybe a comment here about why?

[egdaniel, 2016/08/11 20:09:15]

Done.

+                glslCaps->fConfigTextureSwizzle[i] = GrSwizzle::BGRA();
+                glslCaps->fConfigOutputSwizzle[i] = GrSwizzle::BGRA();
+            } else {
+                glslCaps->fConfigTextureSwizzle[i] = GrSwizzle::RGBA();
+            }
         }
     }