WebGL 2: make sure VertexAttrib type match the corresponding attrib type in shader

gpu/command_buffer/service/vertex_attrib_manager.cc

Index: gpu/command_buffer/service/vertex_attrib_manager.cc
diff --git a/gpu/command_buffer/service/vertex_attrib_manager.cc b/gpu/command_buffer/service/vertex_attrib_manager.cc
index 76883dc0f3fe2e956e9017ea82970d0b407e3fb1..5f71a02d7b8f8ecbd30314a05349a2152d0f4e47 100644
--- a/gpu/command_buffer/service/vertex_attrib_manager.cc
+++ b/gpu/command_buffer/service/vertex_attrib_manager.cc
@@ -127,6 +127,8 @@ VertexAttribManager::~VertexAttribManager() {
 void VertexAttribManager::Initialize(uint32_t max_vertex_attribs,
                                      bool init_attribs) {
   vertex_attribs_.resize(max_vertex_attribs);
+  attrib_base_type_mask_ = 0u;
+  attrib_written_mask_ = 0u;
 
   for (uint32_t vv = 0; vv < vertex_attribs_.size(); ++vv) {
     vertex_attribs_[vv].set_index(vv);