Make library basename generation more robust.

The aim is to turn (e.g.) libmonochrome.so into monochrome, but in the
secondary abi case the path passed has a directory component, which
means that an incorrect library name is generated.

This CL changes the implementation to be more robust to directory
components and the length of the extension.

Bug: 988041
Change-Id: Idfca8a38bbb4fdd2a136a64f14c9f00b675776c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1720876Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Tobias Sargeant <tobiasjs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681853}

build/android/gyp/write_native_libraries_java.py

@@ -70,9 +70,14 @@ def main():
           continue
         lib_paths.append(line)
 
+  def LibBasename(path):
+    filename = os.path.split(path)[1]
+    base = os.path.splitext(filename)[0]
+    return base[3:]  # remove lib prefix
+
   # Convert to "base" library names: e.g. libfoo.so -> foo.
   native_libraries_list = (
-      '{%s}' % ','.join(['"%s"' % s[3:-3] for s in lib_paths]))
+      '{%s}' % ','.join(['"%s"' % LibBasename(s) for s in lib_paths]))
 
   def bool_str(value):
     if value: