Work around CopyTexImage2D issue on Intel Mac OSX 10.12

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 8f7c3f4395b5605e8998d9621c785ccd9a9f4758..fec327827c3e838f62d31dd6bf2d7911ec04bedd 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -13377,6 +13377,18 @@ void GLES2DecoderImpl::DoCopyTexImage2D(
   } else {
     GLenum final_internal_format = TextureManager::AdjustTexInternalFormat(
         feature_info_.get(), internal_format);
+    if (workarounds().init_two_cube_map_levels_before_copyteximage &&
+        texture->target() == GL_TEXTURE_CUBE_MAP &&
+        target != GL_TEXTURE_CUBE_MAP_POSITIVE_X) {
+      for (int i = 0; i < 2; ++i) {
+        TextureManager::DoTexImageArguments args = {
+          target, i, final_internal_format, 1, 1, 1, border,
+          format, type, nullptr, 1, 0,
+          TextureManager::DoTexImageArguments::kTexImage2D };
+        texture_manager()->WorkaroundCopyTexImageCubeMap(&texture_state_,

[Zhenyao Mo, 2016/10/11 03:10:18]

Here is my question: 

WorkaroundCopyTexImageCubeMap() call TextureManager::DoTexImage(), with
internal_format (LUMINANCE_ALPHA) already correctly mapped to
final_internal_format (RG), but format is still LUMINANCE_ALPHA.

That's why I don't understand how DoTexImage() could succeed? Or is there a
place format is also mapped and I missed it? 

[qiankun, 2016/10/11 03:18:19]

In TextureManager::DoTexImage, format is translated (i.e.
AdjustTexFormat(feature_info_.get(), args.format)) when calling glTexImage2D so
DoTexImage could succeed.
See:
https://cs.chromium.org/chromium/src/gpu/command_buffer/service/texture_manag...

+            &state_, &framebuffer_state_, texture_ref, func_name, args);
+      }
+    }
 
     // The service id and target of the texture attached to READ_FRAMEBUFFER.
     GLuint source_texture_service_id = 0;
@@ -13432,7 +13444,7 @@ void GLES2DecoderImpl::DoCopyTexImage2D(
 
       glDeleteTextures(1, &temp_texture);
     } else {
-      if (workarounds().do_teximage_before_copyteximage_to_cube_map &&
+      if (workarounds().init_one_cube_map_level_before_copyteximage &&
           texture->target() == GL_TEXTURE_CUBE_MAP &&
           target != GL_TEXTURE_CUBE_MAP_POSITIVE_X) {
         TextureManager::DoTexImageArguments args = {