Revert "Don't initialize Ozone platform if running unit tests with OSMesa"

This reverts commit b1dfa83e.

Broke Linux ChromiumOS Ozone Tests:
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Ozone%20Tests%20%281%29/builds/5338/steps/interactive_ui_tests/logs/stdio

TBR=gusfernandez@chromium.org
BUG=

Review URL: https://codereview.chromium.org/682853002

Cr-Commit-Position: refs/heads/master@{#301464}

ui/gl/gl_implementation_ozone.cc

@@ -38,12 +38,12 @@ bool InitializeStaticGLBindings(GLImplementation implementation) {
   // unit tests have initialized with kGLImplementationMock, we don't want to
   // later switch to another GL implementation.
   DCHECK_EQ(kGLImplementationNone, GetGLImplementation());
+  ui::OzonePlatform::InitializeForGPU();
 
   switch (implementation) {
     case kGLImplementationOSMesaGL:
       return InitializeStaticGLBindingsOSMesaGL();
     case kGLImplementationEGLGLES2:
-      ui::OzonePlatform::InitializeForGPU();
       if (!ui::SurfaceFactoryOzone::GetInstance()->LoadEGLGLES2Bindings(
               base::Bind(&AddGLNativeLibrary),
               base::Bind(&SetGLGetProcAddressProc)))