add support for GL_EXT_debug_marker

This extension is always added to the GL_EXTENSIONS
extension string for the current GL context, regardless
of if it's supported by the h/w driver.

The extension itself will be handled by GLES_trace (eventually),
when GLES_trace is not enabled, it'll result to a no-op.

If the h/w implementation has this extension, we'll call that version
instead of our dummy version.

Change-Id: Ie5dd3387c4d45cd5ed5f03b73bda6045620a96bc
diff --git a/opengl/libs/EGL/egl_object.cpp b/opengl/libs/EGL/egl_object.cpp
index 26e8c3e..b660c53 100644
--- a/opengl/libs/EGL/egl_object.cpp
+++ b/opengl/libs/EGL/egl_object.cpp
@@ -62,5 +62,41 @@
 }
 
 // ----------------------------------------------------------------------------
+
+egl_context_t::egl_context_t(EGLDisplay dpy, EGLContext context, EGLConfig config,
+        int impl, egl_connection_t const* cnx, int version) :
+    egl_object_t(get_display(dpy)), dpy(dpy), context(context),
+            config(config), read(0), draw(0), impl(impl), cnx(cnx),
+            version(version)
+{
+}
+
+void egl_context_t::onLooseCurrent() {
+    read = NULL;
+    draw = NULL;
+}
+
+void egl_context_t::onMakeCurrent(EGLSurface draw, EGLSurface read) {
+    this->read = read;
+    this->draw = draw;
+
+    /*
+     * Here we cache the GL_EXTENSIONS string for this context and we
+     * add the extensions always handled by the wrapper
+     */
+
+    if (gl_extensions.isEmpty()) {
+        // call the implementation's glGetString(GL_EXTENSIONS)
+        const char* exts = (const char *)gEGLImpl[impl].hooks[version]->gl.glGetString(GL_EXTENSIONS);
+        gl_extensions.setTo(exts);
+        if (gl_extensions.find("GL_EXT_debug_marker") < 0) {
+            String8 temp("GL_EXT_debug_marker ");
+            temp.append(gl_extensions);
+            gl_extensions.setTo(temp);
+        }
+    }
+}
+
+// ----------------------------------------------------------------------------
 }; // namespace android
 // ----------------------------------------------------------------------------