Blacklist MSAA for GPU Raster on Intel GPUs

gpu/command_buffer/service/feature_info.cc

Index: gpu/command_buffer/service/feature_info.cc
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index c21815c08abcc013b64b1e43cc08fb8f21012986..f08291301591a7c37b80348c5c1342781b2997c1 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -231,20 +231,23 @@ void FeatureInfo::InitializeBasicState(const base::CommandLine* command_line) {
       command_line->HasSwitch(switches::kDisableGLSLTranslator);
 
   unsafe_es3_apis_enabled_ = false;
-}
 
-bool FeatureInfo::Initialize() {
-  disallowed_features_ = DisallowedFeatures();
-  InitializeFeatures();
-  return true;
+  // Default context_type_ to a GLES2 Context.
+  context_type_ = CONTEXT_TYPE_OPENGLES2;
 }
 
-bool FeatureInfo::Initialize(const DisallowedFeatures& disallowed_features) {
+bool FeatureInfo::Initialize(ContextType context_type,
+                             const DisallowedFeatures& disallowed_features) {
   disallowed_features_ = disallowed_features;
+  context_type_ = context_type;
   InitializeFeatures();
   return true;
 }
 
+bool FeatureInfo::InitializeForTesting() {
+  return Initialize(CONTEXT_TYPE_OPENGLES2, DisallowedFeatures());
+}
+
 bool IsGL_REDSupportedOnFBOs() {
   // Skia uses GL_RED with frame buffers, unfortunately, Mesa claims to support
   // GL_EXT_texture_rg, but it doesn't support it on frame buffers.  To fix
@@ -1122,6 +1125,23 @@ void FeatureInfo::InitializeFeatures() {
     // but we emulate ES 3.0 on top of Desktop GL 4.2+.
     feature_flags_.emulate_primitive_restart_fixed_index = true;
   }
+
+  if (workarounds_.disable_msaa_on_non_webgl_contexts) {

[Zhenyao Mo, 2015/09/30 23:50:12]

This is inconsistent with the rest of the code.  Basically you should check this
workaround where you set these flags earlier in this function, not resetting
them in the end.

[ericrk, 2015/10/01 17:13:11]

yup, good point - restructured this.

+    // crbug.com/527565 - On some GPUs, MSAA does not perform acceptably for
+    // rasterization. We disable it on non-WebGL contexts. For WebGL contexts
+    // we leave it up to the site to decide whether to enable MSAA.
+    switch (context_type_) {
+      case CONTEXT_TYPE_WEBGL1:
+      case CONTEXT_TYPE_WEBGL2:
+        // WebGL contexts, ignore this flag.
+        break;
+      case CONTEXT_TYPE_OPENGLES2:
+      case CONTEXT_TYPE_OPENGLES3:
+        // Non-WebGL context, disable multisampling.
+        feature_flags_.chromium_framebuffer_multisample = false;
+        feature_flags_.multisampled_render_to_texture = false;
+    }
+  }
 }
 
 bool FeatureInfo::IsES3Capable() const {