AAPT2: Allow truncating of package names

ResTable_package header only allows 127 UTF-16 characters, so AAPT
would truncate the real package name to fit. AAPT2 would error-out
on any package name longer than 127 UTF-16 characters. This strictness
is not required except when building shared libraries, which use the
full package name as a way of identifying the runtime assigned
package ID to package name mapping.

Bug: 36940145
Test: make aapt2_tests
Change-Id: I7d2b7e50c7ab30c6a6c4f15d310e711f68e35091
diff --git a/tools/aapt2/cmd/Diff.cpp b/tools/aapt2/cmd/Diff.cpp
index fdc89b2..1a6f348 100644
--- a/tools/aapt2/cmd/Diff.cpp
+++ b/tools/aapt2/cmd/Diff.cpp
@@ -31,6 +31,11 @@
   DiffContext() : name_mangler_({}), symbol_table_(&name_mangler_) {
   }
 
+  PackageType GetPackageType() override {
+    // Doesn't matter.
+    return PackageType::kApp;
+  }
+
   const std::string& GetCompilationPackage() override {
     return empty_;
   }