Generate INVALID_OPERATION if feedback loops exist in CopyTex{Sub}Image2D.

gpu/command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "gpu/command_buffer/common/gles2_cmd_format.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
@@ skipping 2004 matching lines @@
       .WillOnce(Return(GL_NO_ERROR))
       .RetiresOnSaturation();
   EXPECT_CALL(*gl_, CopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, 1, 1, 0))
       .Times(1)
       .RetiresOnSaturation();
   EXPECT_CALL(*gl_, GetError())
       .WillOnce(Return(GL_NO_ERROR))
       .RetiresOnSaturation();
   CopyTexImage2D cmd;
   cmd.Init(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, 1, 1);
+  // Unbind fbo and bind again after CopyTexImage2D tp avoid feedback loops.
+  if (bound_fbo) {
+    DoBindFramebuffer(GL_FRAMEBUFFER, 0, 0);
+  }
   EXPECT_EQ(error::kNoError, ExecuteCmd(cmd));
+  if (bound_fbo) {
+    DoBindFramebuffer(
+        GL_FRAMEBUFFER, client_framebuffer_id_, kServiceFramebufferId);
+  }
   EXPECT_FALSE(framebuffer_manager->IsComplete(framebuffer));
 
   // Test deleting texture marks fbo as not complete.
   framebuffer_manager->MarkAsComplete(framebuffer);
   EXPECT_TRUE(framebuffer_manager->IsComplete(framebuffer));
   DoDeleteTexture(kFBOClientTextureId, kFBOServiceTextureId);
 
   if (bound_fbo) {
     EXPECT_FALSE(framebuffer_manager->IsComplete(framebuffer));
   } else {
@@ skipping 350 matching lines @@
   EXPECT_EQ(1, result->GetNumResults());
   EXPECT_EQ(GL_NO_ERROR, GetGLError());
 }
 
 // TODO(gman): PixelStorei
 
 // TODO(gman): SwapBuffers
 
 }  // namespace gles2
 }  // namespace gpu