Update build configuration for eLinux after update to Chromium 37.

The build configuration requires the following changes:
- toolkit_views=1: for native_theme_aura, as otherwise
  nine_image_painter_factory.cc would be excluded.
- use_system_harfbuzz=0: we do not want to rely on this
  being provided on the system, therefore being explicit.
- want_separate_host_toolset=1: assures that icuuc gyp
  target will be available.

The file gl_surface_ozone.cc must be added to the exclusion
list to avoid duplicate symbols with gl_surface_at.cpp.

The defines EGL_API_FB and LINUX must be set to 1,
to explicitly define that we are using EGL and are building
for a linux target.

Change-Id: If6722ecbfd0655fe7852d52a606f27c18304f717
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>