Add post upload hook to substitute hashtags for their mapped text

HASHTAGS

Index: HASHTAGS
diff --git a/HASHTAGS b/HASHTAGS
new file mode 100644
index 0000000000000000000000000000000000000000..9eb2003dda857ceb9c3494adcfef4d8d3a16039d
--- /dev/null
+++ b/HASHTAGS
@@ -0,0 +1,16 @@
+# This file is used by the post upload hook in the PRESUBMIT file to
+# automatically change a CL's description based on the specified hashtags.
+# Please see skia:3586 for more details.
+#
+# The format of this file is:
+# hashtag_name,mapped_text
+#
+# Here are some examples:
+# * "projectxyz, BUG=skia:123" would convert "#projectxyz" into "BUG=skia:123".
+# * "notry, NOTRY=true" would convert "#notry" into "NOTRY=true".
+
+dummyproject,BUG=skia:2139,BUG=skia:2812
+notry,NOTRY=true
+nocommit,COMMIT=false
+try_android_test_n7_d,CQ_INCLUDE_TRYBOTS=client.skia.android:Test-Android-Nexus7-Tegra3-Arm7-Debug
+try_android_test_n7_r,CQ_INCLUDE_TRYBOTS=client.skia.android:Test-Android-Nexus7-Tegra3-Arm7-Release