More material updates to DocumentsUI.

All assets cut as alpha variants so we apply desired tinting at
runtime.  Small script to automatically generate XML resources.

Bug: 15836082, 16658537
Change-Id: I803b3f0bf6f121194a5445fd1c6600fabaf28f60
diff --git a/packages/DocumentsUI/wrap_alpha.py b/packages/DocumentsUI/wrap_alpha.py
new file mode 100644
index 0000000..92a3d59
--- /dev/null
+++ b/packages/DocumentsUI/wrap_alpha.py
@@ -0,0 +1,47 @@
+#!/usr/bin/python
+
+import os
+
+"""
+# assume everything needs alpha suffixes
+for root, dirs, files in os.walk('.'):
+    if "res/drawable-" not in root: continue
+
+    for before in files:
+        if "_alpha.png" in before: continue
+
+        after = before.replace(".png", "_alpha.png")
+        os.rename(os.path.join(root, before), os.path.join(root, after))
+"""
+
+# build xml redirection
+for root, dirs, files in os.walk('.'):
+    if "res/drawable-" not in root: continue
+
+    for src in files:
+        if not src.endswith(".png"): continue
+        src = src[0:-4]
+
+        src_clause = '\n    android:src="@drawable/%s"' % (src)
+
+        alpha = src.endswith("_alpha")
+        if alpha:
+            src = src[0:-6]
+            if "ic_doc" in src or "ic_root" in src or "ic_grid_folder" in src:
+                alpha_clause = '\n    android:tint="@*android:color/secondary_text_material_light"'
+            else:
+                alpha_clause = '\n    android:tint="?android:attr/colorControlNormal"'
+        else:
+            alpha_clause = ''
+
+        am = src.endswith("_am")
+        if am:
+            src = src[0:-3]
+            am_clause = '\n    android:autoMirrored="true"'
+        else:
+            am_clause = ''
+
+        with open("res/drawable/%s.xml" % (src), 'w') as xml:
+            xml.write("""<?xml version="1.0" encoding="utf-8"?>
+<bitmap xmlns:android="http://schemas.android.com/apk/res/android"%s%s%s />
+""" % (src_clause, alpha_clause, am_clause))