gpu: introduce DISABLE_TEXTURE_STORAGE workaround for mesa

gpu/command_buffer/tests/gl_texture_storage_unittest.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 <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
 #include "gpu/command_buffer/tests/gl_manager.h"
 #include "gpu/command_buffer/tests/gl_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ skipping 31 matching lines @@
   GLManager gl_;
   GLuint tex_;
   GLuint fbo_;
   bool extension_available_;
 };
 
 TEST_F(TextureStorageTest, CorrectPixels) {
   if (!extension_available_)
     return;
 
+  // TODO(dshwang): After fixing mesa bug, which crashes on updating immutable
+  // texture bound to FBO, remove this workaround. crbug.com/521904

[piman, 2015/08/19 21:07:21]

Is this something that should be fixed / worked around on the service side? It
sounds like a client could cause a GPU process crash (and then maybe worse?)
with this pattern?

[dshwang, 2015/08/20 07:47:46]

right, client can kill gpu process via this pattern.
let me add workaround as you mentioned

[dshwang, 2015/08/20 15:41:24]

Done.

+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0,
+                         0);
+
   glTexStorage2DEXT(GL_TEXTURE_2D, 2, GL_RGBA8_OES, 2, 2);
 
   uint8 source_pixels[16] = {
       1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4
   };
   glTexSubImage2D(GL_TEXTURE_2D,
                   0,
                   0, 0,
                   2, 2,
                   GL_RGBA, GL_UNSIGNED_BYTE,
                   source_pixels);
+
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                         tex_, 0);
+
   EXPECT_TRUE(GLTestHelper::CheckPixels(0, 0, 2, 2, 0, source_pixels));
 }
 
 TEST_F(TextureStorageTest, IsImmutable) {
   if (!extension_available_)
     return;
 
   glTexStorage2DEXT(GL_TEXTURE_2D, 1, GL_RGBA8_OES, 4, 4);
 
   GLint param = 0;
@@ skipping 76 matching lines @@
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                NULL);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
 }
 
 }  // namespace gpu