Runtime resource overlay, iteration 1.

Runtime resource overlay allows unmodified applications to appear
as if they had been compiled with additional resources defined. See
libs/utils/README for more information.

This commit is the first iteration of runtime resource overlay. It
provides the actual overlay modifications and loading of trusted overlay
packages (ie residing in /vendor) targeting framework-res.apk.

This commit loads exactly one overlay package. The overlay,
if present, must target framework-res.apk and be located at
/vendor/overlay/framework/framework-res.apk.

Change-Id: If26ee7754813004a96c043dba37fbe99fa3919db
diff --git a/tools/aapt/Main.cpp b/tools/aapt/Main.cpp
index 266a02f..1e63131 100644
--- a/tools/aapt/Main.cpp
+++ b/tools/aapt/Main.cpp
@@ -68,6 +68,7 @@
         "        [-S resource-sources [-S resource-sources ...]] "
         "        [-F apk-file] [-J R-file-dir] \\\n"
         "        [--product product1,product2,...] \\\n"
+        "        [-o] \\\n"
         "        [raw-files-dir [raw-files-dir] ...]\n"
         "\n"
         "   Package the android resources.  It will read assets and resources that are\n"
@@ -105,6 +106,7 @@
         "   -j  specify a jar or zip file containing classes to include\n"
         "   -k  junk path of file(s) added\n"
         "   -m  make package directories under location specified by -J\n"
+        "   -o  create overlay package (ie only resources; expects <overlay-package> in manifest)\n"
 #if 0
         "   -p  pseudolocalize the default configuration\n"
 #endif
@@ -275,6 +277,9 @@
             case 'm':
                 bundle.setMakePackageDirs(true);
                 break;
+            case 'o':
+                bundle.setIsOverlayPackage(true);
+                break;
 #if 0
             case 'p':
                 bundle.setPseudolocalize(true);