Add a gpu driver bug workaround to count in all varyings in packing check.

gpu/command_buffer/service/program_manager.h

Index: gpu/command_buffer/service/program_manager.h
diff --git a/gpu/command_buffer/service/program_manager.h b/gpu/command_buffer/service/program_manager.h
index 50273e9d25bc74acdea834cbe02eea34ff726d42..9ec31b9dee1968134d2f899d5e4eadc8f53f812d 100644
--- a/gpu/command_buffer/service/program_manager.h
+++ b/gpu/command_buffer/service/program_manager.h
@@ -33,6 +33,11 @@ class GPU_EXPORT Program : public base::RefCounted<Program> {
  public:
   static const int kMaxAttachedShaders = 2;
 
+  enum VaryingsPackingOption {
+    kCountOnlyStaticallyUsed,
+    kCountAll
+  };
+
   struct UniformInfo {
     UniformInfo();
     UniformInfo(
@@ -156,6 +161,7 @@ class GPU_EXPORT Program : public base::RefCounted<Program> {
   bool Link(ShaderManager* manager,
             ShaderTranslator* vertex_translator,
             ShaderTranslator* fragment_shader,
+            VaryingsPackingOption varyings_packing_option,
             const ShaderCacheCallback& shader_callback);
 
   // Performs glValidateProgram and related activities.
@@ -199,7 +205,7 @@ class GPU_EXPORT Program : public base::RefCounted<Program> {
 
   // Return false if varyings can't be packed into the max available
   // varying registers.
-  bool CheckVaryingsPacking() const;
+  bool CheckVaryingsPacking(VaryingsPackingOption option) const;
 
   // Visible for testing
   const LocationMap& bind_attrib_location_map() const {