Reset TexImage2D base level to workaround Intel mac driver bug

gpu/command_buffer/service/texture_manager.cc

Index: gpu/command_buffer/service/texture_manager.cc
diff --git a/gpu/command_buffer/service/texture_manager.cc b/gpu/command_buffer/service/texture_manager.cc
index 3a655827f75efa7ac3312f866295dc400fda5642..38a6918c7dbfc5fc9d68cfd53fc6729abb76613e 100644
--- a/gpu/command_buffer/service/texture_manager.cc
+++ b/gpu/command_buffer/service/texture_manager.cc
@@ -3261,12 +3261,20 @@ void TextureManager::DoTexImage(
           AdjustTexFormat(feature_info_.get(), args.format), args.type,
           args.pixels);
     } else {
+      if (feature_info_->workarounds().reset_teximage2d_base_level) {
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);

[Ken Russell (switch to Gerrit), 2017/04/28 19:04:25]

Does this have the correct effect in all cases? The glTexImage2D call below
refers to args.target, not GL_TEXTURE_2D. Is this necessary even when
args.target != GL_TEXTURE_2D?

[yizhou.jiang, 2017/06/09 07:58:16]

No, I have only investigated GL_TEXTURE_2D, I will add check if args.target is
GL_TEXTURE_2D.

+      }
       glTexImage2D(
           args.target, args.level,
           AdjustTexInternalFormat(feature_info_.get(), args.internal_format),
           args.width, args.height, args.border,
           AdjustTexFormat(feature_info_.get(), args.format), args.type,
           args.pixels);
+      if (feature_info_->workarounds().reset_teximage2d_base_level) {
+        Texture* texture = texture_ref->texture();
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL,
+                        texture->base_level());
+      }
     }
   }
   GLenum error = ERRORSTATE_PEEK_GL_ERROR(error_state, function_name);