[Android WebView] Remove WebView-specific "exceptional" paths list

1. Remove WebView-specific "prune paths", as all of them are now in
   Chromium-wide PRUNE_PATHS list from licenses.py
   (https://codereview.chromium.org/1153763006)

2. Extract "FindThirdPartyDirsWithFiles" in licenses.py, which can
   also be used in webview_licenses.py

3. Remove known_issues.py, as this was the list of dirs that are
   "incompatibly licensed" w.r.t. Android tree (in fact, we could remove
   this list earlier, when I was removing the "incompatible directories"
   list generator, but I was misguided by the fact that this list was
   also used in other code, although its effect on that code is actually
   void).

BUG=486158

Review URL: https://codereview.chromium.org/1155163007

Cr-Commit-Position: refs/heads/master@{#331792}

1 files changed, 6 insertions, 2 deletions

diff --git a/tools/licenses.py b/tools/licenses.py
index b900edf..8790c8d 100755
--- a/tools/licenses.py
+++ b/tools/licenses.py
@@ -397,12 +397,16 @@ def FindThirdPartyDirs(prune_paths, root):
     return third_party_dirs
 
 
+def FindThirdPartyDirsWithFiles(root):
+    third_party_dirs = FindThirdPartyDirs(PRUNE_PATHS, root)
+    return FilterDirsWithFiles(third_party_dirs, root)
+
+
 def ScanThirdPartyDirs(root=None):
     """Scan a list of directories and report on any problems we find."""
     if root is None:
       root = os.getcwd()
-    third_party_dirs = FindThirdPartyDirs(PRUNE_PATHS, root)
-    third_party_dirs = FilterDirsWithFiles(third_party_dirs, root)
+    third_party_dirs = FindThirdPartyDirsWithFiles(root)
 
     errors = []
     for path in sorted(third_party_dirs):