Disallow active attrib aliasing at shader program link time.

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 c55d9e387b11b81eb2f4448a4670fde2cade8a66..6beca1018c703b442ff6e08f71d84282563ccaab 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -4860,7 +4860,13 @@ void GLES2DecoderImpl::DoBindAttribLocation(
   if (!program) {
     return;
   }
+  // At this point, the program's shaders may not be translated yet,
+  // therefore, we may not find the hashed attribute name.
+  // glBindAttribLocation call with original name is useless.
+  // So instead, we should simply cache the binding, and then call
+  // Program::ExecuteBindAttribLocationCalls() right before link.
   program->SetAttribLocationBinding(name, static_cast<GLint>(index));
+  // TODO(zmo): Get rid of the following glBindAttribLocation call.

[Zhenyao Mo, 2014/10/11 00:25:41]

I didn't do this in this CL, but simply add a TODO to remind myself.

This is because 1) it's orthogonal to this CL; 2) it involves a bunch of test
changes (mostly test expectations).

   glBindAttribLocation(program->service_id(), index, name);
 }