Revert "Implement GL_KHR_debug."

This reverts commit 6c521b7a70a53b1c9f7762e53e34b5a8146b0f7b.

Change-Id: I6ff981198e31f34d3e405edea6277ee75516d6ee
Reviewed-on: https://chromium-review.googlesource.com/319820
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/Program.cpp b/src/libANGLE/Program.cpp
index e21c8f4..4a99c88 100644
--- a/src/libANGLE/Program.cpp
+++ b/src/libANGLE/Program.cpp
@@ -223,8 +223,7 @@
 }
 
 Program::Data::Data()
-    : mLabel(),
-      mAttachedFragmentShader(nullptr),
+    : mAttachedFragmentShader(nullptr),
       mAttachedVertexShader(nullptr),
       mTransformFeedbackBufferMode(GL_INTERLEAVED_ATTRIBS),
       mBinaryRetrieveableHint(false)
@@ -244,11 +243,6 @@
     }
 }
 
-const std::string &Program::Data::getLabel()
-{
-    return mLabel;
-}
-
 const LinkedUniform *Program::Data::getUniformByName(const std::string &name) const
 {
     for (const LinkedUniform &linkedUniform : mUniforms)
@@ -334,16 +328,6 @@
     SafeDelete(mProgram);
 }
 
-void Program::setLabel(const std::string &label)
-{
-    mData.mLabel = label;
-}
-
-const std::string &Program::getLabel() const
-{
-    return mData.mLabel;
-}
-
 bool Program::attachShader(Shader *shader)
 {
     if (shader->getType() == GL_VERTEX_SHADER)