current program can be null in ES2/ES3 contexts.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 542d3776531a4dd1212291ca54b655899a919831..2b5a562407f831e678338f617335d971489b1108 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -3078,8 +3078,7 @@ bool GLES2DecoderImpl::Initialize(
   state_.indexed_uniform_buffer_bindings = new IndexedBufferBindingHost(
       group_->max_uniform_buffer_bindings(), needs_emulation);
 
-  state_.InitGenericAttribBaseType(group_->max_vertex_attribs());
-  state_.attrib_values.resize(group_->max_vertex_attribs());
+  state_.InitGenericAttribs(group_->max_vertex_attribs());
   vertex_array_manager_.reset(new VertexArrayManager());
 
   GLuint default_vertex_attrib_service_id = 0;
@@ -9137,21 +9136,34 @@ void GLES2DecoderImpl::RestoreStateForSimulatedFixedAttribs() {
 }
 
 bool GLES2DecoderImpl::AttribsTypeMatch() {
-  for (uint32_t index = 0; index < group_->max_vertex_attribs(); index += 16) {
-    uint32_t shader_attrib_written_mask =
-        state_.current_program->vertex_input_type_written_mask(index);
-    uint32_t vao_attrib_enabled_mask =
-        state_.vertex_attrib_manager->attrib_enabled_mask(index);
-
-    uint32_t vertex_attrib_base_type_mask =
-        (~vao_attrib_enabled_mask &
-         state_.GetGenericVertexAttribBaseTypeMask(index)) |
-        (vao_attrib_enabled_mask &
-         state_.vertex_attrib_manager->attrib_base_type_mask(index));
-
-    if ((state_.current_program->vertex_input_base_type_mask(index)
-         & shader_attrib_written_mask) !=
-         (vertex_attrib_base_type_mask & shader_attrib_written_mask)) {
+  if (!state_.current_program.get())
+    return true;

[Zhenyao Mo, 2016/07/23 16:10:40]

This is actually the crash fix.  Everything else is cleanup.

[yunchao, 2016/07/24 04:52:13]

I see... 

+  const std::vector<uint32_t>& shader_attrib_active_mask =
+      state_.current_program->vertex_input_active_mask();
+  const std::vector<uint32_t>& shader_attrib_type_mask =
+      state_.current_program->vertex_input_base_type_mask();
+  const std::vector<uint32_t>& generic_vertex_attrib_type_mask =
+      state_.generic_attrib_base_type_mask();
+  const std::vector<uint32_t>& vertex_attrib_array_enabled_mask =
+      state_.vertex_attrib_manager->attrib_enabled_mask();
+  const std::vector<uint32_t>& vertex_attrib_array_type_mask =
+      state_.vertex_attrib_manager->attrib_base_type_mask();
+  DCHECK_EQ(shader_attrib_active_mask.size(),
+            shader_attrib_type_mask.size());
+  DCHECK_EQ(shader_attrib_active_mask.size(),
+            generic_vertex_attrib_type_mask.size());
+  DCHECK_EQ(shader_attrib_active_mask.size(),
+            vertex_attrib_array_enabled_mask.size());
+  DCHECK_EQ(shader_attrib_active_mask.size(),
+            vertex_attrib_array_type_mask.size());
+  for (size_t ii = 0; ii < shader_attrib_active_mask.size(); ++ii) {

[Zhenyao Mo, 2016/07/23 16:10:40]

This is a minor optimization. We can just query the entire masks altogether.

+    uint32_t vertex_attrib_source_type_mask =
+        (~vertex_attrib_array_enabled_mask[ii] &
+         generic_vertex_attrib_type_mask[ii]) |
+        (vertex_attrib_array_enabled_mask[ii] &
+         vertex_attrib_array_type_mask[ii]);
+    if ((shader_attrib_type_mask[ii] & shader_attrib_active_mask[ii]) !=
+        (vertex_attrib_source_type_mask & shader_attrib_active_mask[ii])) {
       return false;
     }
   }