Use a packed enum for buffer targets.

BUG=angleproject:2169

Change-Id: I4e08973d0e16404b7b8ee2f119e29ac502e28669
Reviewed-on: https://chromium-review.googlesource.com/723865
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/validationES31.cpp b/src/libANGLE/validationES31.cpp
index 7db0856..d44d17f 100644
--- a/src/libANGLE/validationES31.cpp
+++ b/src/libANGLE/validationES31.cpp
@@ -356,7 +356,7 @@
         return false;
     }
 
-    gl::Buffer *drawIndirectBuffer = state.getDrawIndirectBuffer();
+    gl::Buffer *drawIndirectBuffer = state.getTargetBuffer(BufferBinding::DrawIndirect);
     if (!drawIndirectBuffer)
     {
         context->handleError(InvalidOperation() << "zero is bound to DRAW_INDIRECT_BUFFER");
@@ -405,7 +405,7 @@
     if (!ValidateDrawIndirectBase(context, mode, indirect))
         return false;
 
-    gl::Buffer *drawIndirectBuffer = state.getDrawIndirectBuffer();
+    gl::Buffer *drawIndirectBuffer = state.getTargetBuffer(BufferBinding::DrawIndirect);
     CheckedNumeric<size_t> checkedOffset(reinterpret_cast<size_t>(indirect));
     // In OpenGL ES3.1 spec, session 10.5, it defines the struct of DrawArraysIndirectCommand
     // which's size is 4 * sizeof(uint).
@@ -439,7 +439,7 @@
     if (!ValidateDrawIndirectBase(context, mode, indirect))
         return false;
 
-    gl::Buffer *drawIndirectBuffer = state.getDrawIndirectBuffer();
+    gl::Buffer *drawIndirectBuffer = state.getTargetBuffer(BufferBinding::DrawIndirect);
     CheckedNumeric<size_t> checkedOffset(reinterpret_cast<size_t>(indirect));
     // In OpenGL ES3.1 spec, session 10.5, it defines the struct of DrawElementsIndirectCommand
     // which's size is 5 * sizeof(uint).