Add ES3 commands GetVertexAttribI{u}iv to GPU command buffer.

gpu/command_buffer/service/vertex_attrib_manager.h

Index: gpu/command_buffer/service/vertex_attrib_manager.h
diff --git a/gpu/command_buffer/service/vertex_attrib_manager.h b/gpu/command_buffer/service/vertex_attrib_manager.h
index 73fa4807d6e785bfa572b7c53eab385f09696db2..b5425e0dc9cb2d33ecf75cbbf727001db2331ef6 100644
--- a/gpu/command_buffer/service/vertex_attrib_manager.h
+++ b/gpu/command_buffer/service/vertex_attrib_manager.h
@@ -65,6 +65,10 @@ class GPU_EXPORT VertexAttrib {
     return divisor_;
   }
 
+  GLboolean integer() const {
+    return integer_;
+  }
+
   bool enabled() const {
     return enabled_;
   }
@@ -118,6 +122,10 @@ class GPU_EXPORT VertexAttrib {
     divisor_ = divisor;
   }
 
+  void SetInteger(GLboolean integer) {
+    integer_ = integer;
+  }
+
   void Unbind(Buffer* buffer);
 
   // The index of this attrib.
@@ -147,6 +155,8 @@ class GPU_EXPORT VertexAttrib {
 
   GLsizei divisor_;
 
+  GLboolean integer_;
+
   // Will be true if this was assigned to a client side array.
   bool is_client_side_array_;
 
@@ -218,6 +228,13 @@ class GPU_EXPORT VertexAttribManager :
     }
   }
 
+  void SetInteger(GLuint index, GLboolean integer) {
+    VertexAttrib* attrib = GetVertexAttrib(index);
+    if (attrib) {
+      attrib->SetInteger(integer);
+    }
+  }
+
   void SetElementArrayBuffer(Buffer* buffer);
 
   Buffer* element_array_buffer() const { return element_array_buffer_.get(); }