Modules: Always resolve native library paths through ClassLoader

Normally, the system linker and Crazy Linker can resolve libraries.
However, if a module is installed via SplitCompat, and hasn't yet been
fully installed, then the module (and libraries) reside at an alternate
location unknown to the linkers.

In order to find these libraries, we need to call on the Java
ClassLoader. This is already being done for production libraries, but
not in the component build case (currently affecting only the Test
Dummy module).

As a result, bundle smoke tests running with "fake install" would fail
with component builds - that scenario is meant to look like the
SplitCompat'ed case.

Bug: 1025316
Change-Id: If2bcf2de85b323e5e14ed70561e3f31d50bf8287
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1922276
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716475}

base/android/bundle_utils.cc

@@ -47,7 +47,10 @@ const void* ReadRelPtr(const int32_t* relptr) {
   return reinterpret_cast<const char*>(relptr) + *relptr;
 }
 
-std::string ResolveLibraryPath(const std::string& library_name) {
+}  // namespace
+
+// static
+std::string BundleUtils::ResolveLibraryPath(const std::string& library_name) {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jstring> java_path = Java_BundleUtils_getNativeLibraryPath(
       env, base::android::ConvertUTF8ToJavaString(env, library_name));
@@ -58,8 +61,6 @@ std::string ResolveLibraryPath(const std::string& library_name) {
   return base::android::ConvertJavaStringToUTF8(env, java_path);
 }
 
-}  // namespace
-
 // static
 bool BundleUtils::IsBundle() {
   return Java_BundleUtils_isBundle(base::android::AttachCurrentThread());

base/android/bundle_utils.h

@@ -18,6 +18,11 @@ class BASE_EXPORT BundleUtils {
   // Returns true if the current build is a bundle.
   static bool IsBundle();
 
+  // Helper function asking Java to resolve a library path. This is required for
+  // resolving a module library made available via SplitCompat, rather than in
+  // its eventual fully-installed state.
+  static std::string ResolveLibraryPath(const std::string& library_name);
+
   // dlopen wrapper that works for partitioned native libraries in dynamic
   // feature modules. This routine looks up the partition's address space in a
   // table of main library symbols, and uses it when loading the feature

components/module_installer/android/module.cc

@@ -55,8 +55,8 @@ void* LoadLibrary(const std::string& library_name,
   library_handle =
       BundleUtils::DlOpenModuleLibraryPartition(library_name, partition_name);
 #elif defined(COMPONENT_BUILD)
-  const std::string lib_name = "lib" + library_name + ".so";
-  library_handle = dlopen(lib_name.c_str(), RTLD_LOCAL);
+  std::string library_path = BundleUtils::ResolveLibraryPath(library_name);
+  library_handle = dlopen(library_path.c_str(), RTLD_LOCAL);
 #else
 #error "Unsupported configuration."
 #endif  // defined(COMPONENT_BUILD)