Autogenerate Repeated Portions of Blit11

Introduces a script to generate Blit11's
BlitShaderType enum and shader mapping functions.

Bug: angleproject:2870
Change-Id: I5b704f55bdde1706614a519ecb0ee3756f7799e0
Reviewed-on: https://chromium-review.googlesource.com/c/1273725
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/scripts/run_code_generation.py b/scripts/run_code_generation.py
index 0dc82d2..92cc20b 100755
--- a/scripts/run_code_generation.py
+++ b/scripts/run_code_generation.py
@@ -62,6 +62,10 @@
         ],
         'script': 'src/libANGLE/renderer/gen_load_functions_table.py',
     },
+    'D3D11 blit shader selection': {
+        'inputs': [],
+        'script': 'src/libANGLE/renderer/d3d/d3d11/gen_blit11helper.py',
+    },
     'D3D11 format': {
         'inputs': [
             'src/libANGLE/renderer/angle_format.py',