Add generation of dependency file for .ap_ package

Make Aapt generate a dependency file in the same directory as the
output ap_ file if the --generate-dependencies flag is set.
This dependency file can then be read by the ant exec loop task
to see whether to repackage resources.

Change-Id: I763679414daf76369700aa599c26dcf78d4de099
diff --git a/tools/aapt/Package.cpp b/tools/aapt/Package.cpp
index 999a5cf..6e2a25c 100644
--- a/tools/aapt/Package.cpp
+++ b/tools/aapt/Package.cpp
@@ -172,6 +172,16 @@
         }
     }
 
+    if (bundle->getGenDependencies()) {
+        // Add this file to the dependency file
+        String8 dependencyFile = outputFile.getBasePath();
+        dependencyFile.append(".d");
+
+        FILE* fp = fopen(dependencyFile.string(), "a");
+        fprintf(fp, "%s \\\n", outputFile.string());
+        fclose(fp);
+    }
+
     assert(result == NO_ERROR);
 
 bail: