gpu: introduce DISABLE_TEXTURE_STORAGE workaround for mesa

gpu/command_buffer/tests/gl_texture_storage_unittest.cc

Index: gpu/command_buffer/tests/gl_texture_storage_unittest.cc
diff --git a/gpu/command_buffer/tests/gl_texture_storage_unittest.cc b/gpu/command_buffer/tests/gl_texture_storage_unittest.cc
index 3006888aa6be6eb6ea13e02bd0c21cf9d061cca5..39bc428b27c48db902368c9cca05f90a25f02c96 100644
--- a/gpu/command_buffer/tests/gl_texture_storage_unittest.cc
+++ b/gpu/command_buffer/tests/gl_texture_storage_unittest.cc
@@ -49,6 +49,11 @@ 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] = {
@@ -60,6 +65,10 @@ TEST_F(TextureStorageTest, CorrectPixels) {
                   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));
 }