opengles emulator: support glEGLImageTargetRenderbufferStorageOES

needed changes to support glEGLImageTargetRenderbufferStorageOES,
added implementation in egl and added tokens to renderControl.

Also fixed function pointers returned by eglGetProcAddress to
return functions that works independant of the current context,
see system/egl/ClientAPIExts.cpp

That makes the egl_image conformance test to pass on the guest.

Change-Id: I580cda82ba0fb44f12b75aa0bbacf5cd9f15f744

tools/emulator/opengl/host/libs/libOpenglRender/FrameBuffer.cpp

@@ -508,6 +508,19 @@ bool FrameBuffer::bindColorBufferToTexture(HandleType p_colorbuffer)
     return (*c).second->bindToTexture();
 }
 
+bool FrameBuffer::bindColorBufferToRenderbuffer(HandleType p_colorbuffer)
+{
+    android::Mutex::Autolock mutex(m_lock);
+
+    ColorBufferMap::iterator c( m_colorbuffers.find(p_colorbuffer) );
+    if (c == m_colorbuffers.end()) {
+        // bad colorbuffer handle
+        return false;
+    }
+
+    return (*c).second->bindToRenderbuffer();
+}
+
 bool FrameBuffer::bindContext(HandleType p_context,
                               HandleType p_drawSurface,
                               HandleType p_readSurface)