Android: Make stack tool work for GN builds

This actually required a couple of changes to the script:
1. Add lib.unstripped to search paths.
2. Respect CHROMIUM_OUTPUT_DIR environment variable.
3. Don't sort by mtime when looking for libraries (resulted in stripped
   version always being selected).

This also stops the script from looking in default symbol locations when
--chrome-symbols-dir is specified.

BUG=543897

Review URL: https://codereview.chromium.org/1412293002

Cr-Commit-Position: refs/heads/master@{#355216}

2 files changed, 41 insertions, 26 deletions

diff --git a/third_party/android_platform/development/scripts/stack b/third_party/android_platform/development/scripts/stack
index c5a56c6..6c60c17 100755
--- a/third_party/android_platform/development/scripts/stack
+++ b/third_party/android_platform/development/scripts/stack
@@ -138,7 +138,7 @@ def main(argv):
     elif option == "--arch":
       symbol.ARCH = value
     elif option == "--chrome-symbols-dir":
-      symbol.CHROME_SYMBOLS_DIR = os.path.join(symbol.CHROME_SYMBOLS_DIR, value)
+      symbol.CHROME_SYMBOLS_DIR = os.path.join(symbol.CHROME_SRC, value)
     elif option == "--more-info":
       more_info = True
     elif option == "--less-info":
@@ -164,7 +164,8 @@ def main(argv):
     rootdir, symbol.SYMBOLS_DIR = UnzipSymbols(zip_arg)
 
   print "Reading Android symbols from", symbol.SYMBOLS_DIR
-  print "Reading Chrome symbols from", symbol.CHROME_SYMBOLS_DIR
+  chrome_search_path = symbol.GetLibrarySearchPaths()
+  print "Searching for Chrome symbols from within", ':'.join(chrome_search_path)
   stack_core.ConvertTrace(lines, more_info)
 
   if rootdir:
diff --git a/third_party/android_platform/development/scripts/symbol.py b/third_party/android_platform/development/scripts/symbol.py
index b72253d..ead0e1a 100755
--- a/third_party/android_platform/development/scripts/symbol.py
+++ b/third_party/android_platform/development/scripts/symbol.py
@@ -29,18 +29,20 @@ import subprocess
 import sys
 import zipfile
 
-CHROME_SRC = os.path.join(os.path.realpath(os.path.dirname(__file__)),
-                          os.pardir, os.pardir, os.pardir, os.pardir)
+sys.path.insert(0, os.path.join(os.path.dirname(__file__),
+                                os.pardir, os.pardir, os.pardir, os.pardir,
+                                'build', 'android'))
+from pylib import constants
+from pylib.symbols import elf_symbolizer
+
+
+CHROME_SRC = constants.DIR_SOURCE_ROOT
 ANDROID_BUILD_TOP = CHROME_SRC
 SYMBOLS_DIR = CHROME_SRC
-CHROME_SYMBOLS_DIR = CHROME_SRC
-
+CHROME_SYMBOLS_DIR = None
 ARCH = "arm"
-
 TOOLCHAIN_INFO = None
 
-sys.path.insert(0, os.path.join(CHROME_SRC, 'build', 'android'))
-from pylib.symbols import elf_symbolizer
 
 # See:
 # http://bugs.python.org/issue14315
@@ -202,10 +204,19 @@ def PathListJoin(prefix_list, suffix_list):
    """
    return [
        os.path.join(prefix, suffix)
-       for prefix in prefix_list for suffix in suffix_list ]
+       for suffix in suffix_list for prefix in prefix_list ]
+
+
+def _GetChromeOutputDirCandidates():
+  """Returns a list of output directories to look in."""
+  if os.environ.get('CHROMIUM_OUTPUT_DIR') or os.environ.get('BUILDTYPE'):
+    return [constants.GetOutDirectory()]
+  return [constants.GetOutDirectory(build_type='Debug'),
+          constants.GetOutDirectory(build_type='Release')]
+
 
 def GetCandidates(dirs, filepart, candidate_fun):
-  """Returns a list of candidate filenames.
+  """Returns a list of candidate filenames, sorted by modification time.
 
   Args:
     dirs: a list of the directory part of the pathname.
@@ -215,21 +226,11 @@ def GetCandidates(dirs, filepart, candidate_fun):
   Returns:
     A list of candidate files ordered by modification time, newest first.
   """
-  out_dir = os.environ.get('CHROMIUM_OUT_DIR', 'out')
-  out_dir = os.path.join(CHROME_SYMBOLS_DIR, out_dir)
-  buildtype = os.environ.get('BUILDTYPE')
-  if buildtype:
-    buildtype_list = [ buildtype ]
-  else:
-    buildtype_list = [ 'Debug', 'Release' ]
-
-  candidates = PathListJoin([out_dir], buildtype_list) + [CHROME_SYMBOLS_DIR]
-  candidates = PathListJoin(candidates, dirs)
-  candidates = PathListJoin(candidates, [filepart])
+  candidates = PathListJoin(dirs, [filepart])
   logging.debug('GetCandidates: prefiltered candidates = %s' % candidates)
   candidates = list(
       itertools.chain.from_iterable(map(candidate_fun, candidates)))
-  candidates = sorted(candidates, key=os.path.getmtime, reverse=True)
+  candidates.sort(key=os.path.getmtime, reverse=True)
   return candidates
 
 def GetCandidateApks():
@@ -241,7 +242,8 @@ def GetCandidateApks():
   Returns:
     list of APK filename which could contain the library.
   """
-  return GetCandidates(['apks'], '*.apk', glob.glob)
+  dirs = PathListJoin(_GetChromeOutputDirCandidates(), ['apks'])
+  return GetCandidates(dirs, '*.apk', glob.glob)
 
 def GetCrazyLib(apk_filename):
   """Returns the name of the first crazy library from this APK.
@@ -294,6 +296,12 @@ def MapDeviceApkToLibrary(device_apk_name):
     if crazy_lib:
       return crazy_lib
 
+def GetLibrarySearchPaths():
+  if CHROME_SYMBOLS_DIR:
+    return [CHROME_SYMBOLS_DIR]
+  dirs = _GetChromeOutputDirCandidates()
+  return PathListJoin(dirs, ['lib.unstripped', 'lib', 'lib.target', '.'])
+
 def GetCandidateLibraries(library_name):
   """Returns a list of candidate library filenames.
 
@@ -303,9 +311,15 @@ def GetCandidateLibraries(library_name):
   Returns:
     A list of matching library filenames for library_name.
   """
-  return GetCandidates(
-      ['lib', 'lib.target', '.'], library_name,
+  candidates = GetCandidates(
+      GetLibrarySearchPaths(), library_name,
       lambda filename: filter(os.path.exists, [filename]))
+  # For GN, candidates includes both stripped an unstripped libraries. Stripped
+  # libraries are always newer. Explicitly look for .unstripped and sort them
+  # ahead.
+  candidates.sort(key=lambda c: int('unstripped' not in c))
+  return candidates
+
 
 def TranslateLibPath(lib):
   # The filename in the stack trace maybe an APK name rather than a library