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/Shader.cpp b/src/libANGLE/Shader.cpp
index bbe9077..6cfa4b9 100644
--- a/src/libANGLE/Shader.cpp
+++ b/src/libANGLE/Shader.cpp
@@ -72,7 +72,7 @@
     return gl::VariableSortOrder(x.type) < gl::VariableSortOrder(y.type);
 }
 
-Shader::Data::Data(GLenum shaderType) : mLabel(), mShaderType(shaderType), mShaderVersion(100)
+Shader::Data::Data(GLenum shaderType) : mShaderType(shaderType), mShaderVersion(100)
 {
 }
 
@@ -103,16 +103,6 @@
     SafeDelete(mImplementation);
 }
 
-void Shader::setLabel(const std::string &label)
-{
-    mData.mLabel = label;
-}
-
-const std::string &Shader::getLabel() const
-{
-    return mData.mLabel;
-}
-
 GLuint Shader::getHandle() const
 {
     return mHandle;