Revert "Re-land "Move sampler validation to the GL layer.""

Build failure on Linux:

In file included from ../../third_party/angle/src/tests/gl_tests/UniformTest.cpp:7:
In file included from ../../third_party/angle/src/tests/test_utils/ANGLETest.h:10:
../../testing/gtest/include/gtest/gtest.h:1392:16: error: comparison of integers of different signs: 'const int' and 'const unsigned int' [-Werror,-Wsign-compare]
  if (expected == actual) {
      ~~~~~~~~ ^  ~~~~~~
../../testing/gtest/include/gtest/gtest.h:1422:12: note: in instantiation of function template specialization 'testing::internal::CmpHelperEQ<int, unsigned int>' requested here
    return CmpHelperEQ(expected_expression, actual_expression, expected,
           ^
../../third_party/angle/src/tests/gl_tests/UniformTest.cpp:487:5: note: in instantiation of function template specialization 'testing::internal::EqHelper<false>::Compare<int, unsigned int>' requested here
    EXPECT_EQ(GL_SAMPLER_2D, type);
    ^

BUG=angleproject:1123

This reverts commit 6cbf4385280c4c1dd97f0882ecb18dbc4c341fd4.

Change-Id: I95279b37d253e3ea78faa53f3773f2dc3d17df95
Reviewed-on: https://chromium-review.googlesource.com/302030
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index bbb4540..bae8389 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -299,6 +299,12 @@
     mFunctions->uniformMatrix4x3fv(uniLoc(location), count, transpose, value);
 }
 
+bool ProgramGL::validateSamplers(gl::InfoLog *infoLog, const gl::Caps &caps)
+{
+    //UNIMPLEMENTED();
+    return true;
+}
+
 void ProgramGL::reset()
 {
     mUniformRealLocationMap.clear();