Build: Switch to Magisk as the built in root [2/2]

Pretty much identical to DirtyUnicorns/android_build@2871a7b

Modified and updated for TWRP 3.0.3-x by @nathanchance

Change-Id: Ic0cc0b6e96723a87298edb5cded9f6ef93c05b9d
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

tools/releasetools/edify_generator.py

@@ -173,6 +173,11 @@ def ValidateSignatures(self, command):
   def RunPersist(self, command):
     self.script.append(('run_program("/tmp/install/bin/persist.sh", "%s");' % command))
 
+  def FlashMagisk(self):
+    self.script.append('package_extract_dir("magisk", "/tmp/magisk");')
+    self.script.append('run_program("/sbin/busybox", "unzip", "/tmp/magisk/magisk.zip", "META-INF/com/google/android/*", "-d", "/tmp/magisk");')
+    self.script.append('run_program("/sbin/sh", "/tmp/magisk/META-INF/com/google/android/update-binary", "dummy", "1", "/tmp/magisk/magisk.zip");')
+
   def ShowProgress(self, frac, dur):
     """Update the progress bar, advancing it over 'frac' over the next
     'dur' seconds.  'dur' may be zero to advance it via SetProgress

tools/releasetools/ota_from_target_files.py

@@ -800,6 +800,14 @@ def output_sink(fn, data):
   script.ShowProgress(0.05, 5)
   script.WriteRawImage("/boot", "boot.img")
 
+  if block_based:
+    script.Print(" ")
+    script.Print("Flashing Magisk...")
+    script.Print(" ")
+    common.ZipWriteStr(output_zip, "magisk/magisk.zip",
+                   ""+input_zip.read("SYSTEM/addon.d/magisk.zip"))
+    script.FlashMagisk()
+    script.Print(" ")
   script.ShowProgress(0.2, 10)
   device_specific.FullOTA_InstallEnd()