Pass Context to setLabel.

This is useful for triggering a dirty state notification for Textures.
It will lead to improvements for program and texture dirty bits.

Bug: angleproject:2966
Change-Id: Iaba625da8a970a558f7d158bfa2f09c964f6761a
Reviewed-on: https://chromium-review.googlesource.com/c/1347669
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/libANGLE/Program.cpp b/src/libANGLE/Program.cpp
index 5e237c2..8a67428 100644
--- a/src/libANGLE/Program.cpp
+++ b/src/libANGLE/Program.cpp
@@ -931,7 +931,7 @@
     return mHandle;
 }
 
-void Program::setLabel(const std::string &label)
+void Program::setLabel(const Context *context, const std::string &label)
 {
     ASSERT(mLinkResolved);
     mState.mLabel = label;