Make MergeAssets respect aapt no-compress extensions for resources

Summary:
Previously, it was respecting aapt's decision on whether to compress any
given resource.  However, aapt2 currently compresses everything, leading
to compressed sounds that cannot be played.

For now, use the aapt extensions list as a double-check.

Test Plan: Integration test.

fbshipit-source-id: c11d1f6

src/com/facebook/buck/android/MergeAssets.java

@@ -174,12 +174,18 @@ public StepExecutionResult execute(ExecutionContext context)
           for (ZipEntry inputEntry = base.getNextEntry();
               inputEntry != null;
               base.closeEntry(), inputEntry = base.getNextEntry()) {
+            String extension = Files.getFileExtension(inputEntry.getName());
+            // Only compress if aapt compressed it and the extension looks compressible.
+            // This is a workaround for aapt2 compressing everything.
+            boolean shouldCompress =
+                inputEntry.getMethod() != ZipEntry.STORED
+                    && !NO_COMPRESS_EXTENSIONS.contains(extension);
             byte[] data = ByteStreams.toByteArray(base);
             addEntry(
                 output,
                 data,
                 inputEntry.getName(),
-                inputEntry.getMethod() == ZipEntry.STORED ? 0 : Deflater.BEST_COMPRESSION,
+                shouldCompress ? Deflater.BEST_COMPRESSION : 0,
                 inputEntry.isDirectory());
           }
         }

test/com/facebook/buck/android/AndroidBinaryIntegrationTest.java

@@ -923,6 +923,8 @@ public void testSimpleAapt2App() throws IOException {
     zipInspector.assertFileExists("res/layout/top_layout.xml");
     zipInspector.assertFileExists("assets/asset_file.txt");
 
+    zipInspector.assertFileIsNotCompressed("res/drawable/tiny_black.png");
+
     Map<String, String> rDotJavaContents =
         parseRDotJavaSmali(outputs.get("//apps/sample:disassemble_app_with_aapt2"));
     Map<String, String> resourceBundleContents =