Added Caching for PreProcessed PNGs

Added a cache management system for pre-processed PNG files
along with unit tests. The cache system will be used if
the --no-crunch flag is passed to AAPT during the package
phase. The cache can be updated by a call to 'aapt crunch'
(see usage statement). Also put in benchmarking code.

Change-Id: I58271fb2ee2f5f9075fd74d4ff6f15e7afabd05c
diff --git a/tools/aapt/tests/MockFileFinder.h b/tools/aapt/tests/MockFileFinder.h
new file mode 100644
index 0000000..da5ea4f
--- /dev/null
+++ b/tools/aapt/tests/MockFileFinder.h
@@ -0,0 +1,55 @@
+//
+// Copyright 2011 The Android Open Source Project
+//
+
+#ifndef MOCKFILEFINDER_H
+#define MOCKFILEFINDER_H
+
+#include <utils/Vector.h>
+#include <utils/KeyedVector.h>
+#include <utils/String8.h>
+
+#include "DirectoryWalker.h"
+
+using namespace android;
+
+class MockFileFinder : public FileFinder {
+public:
+    MockFileFinder (KeyedVector<String8, KeyedVector<String8,time_t> >& files)
+        : mFiles(files)
+    {
+        // Nothing left to do
+    };
+
+    /**
+     * findFiles implementation for the abstraction.
+     * PRECONDITIONS:
+     *  No checking is done, so there MUST be an entry in mFiles with
+     *  path matching basePath.
+     *
+     * POSTCONDITIONS:
+     *  fileStore is filled with a copy of the data in mFiles corresponding
+     *  to the basePath.
+     */
+
+    virtual bool findFiles(String8 basePath, Vector<String8>& extensions,
+                           KeyedVector<String8,time_t>& fileStore,
+                           DirectoryWalker* dw)
+    {
+        const KeyedVector<String8,time_t>* payload(&mFiles.valueFor(basePath));
+        // Since KeyedVector doesn't implement swap
+        // (who doesn't use swap??) we loop and add one at a time.
+        for (size_t i = 0; i < payload->size(); ++i) {
+            fileStore.add(payload->keyAt(i),payload->valueAt(i));
+        }
+        return true;
+    }
+
+private:
+    // Virtual mapping between "directories" and the "files" contained
+    // in them
+    KeyedVector<String8, KeyedVector<String8,time_t> > mFiles;
+};
+
+
+#endif // MOCKFILEFINDER_H
\ No newline at end of file