Revert of Revert "Revert of Telemetry: Last ditch effort to dump symbols on...

Revert of Revert "Revert of Telemetry: Last ditch effort to dump symbols on tab crashes if none are found (ht… (https://codereview.chromium.org/444453002/)

Reason for revert:
Macbots are getting stuck here:
[       OK ] page_runner_unittest.PageRunnerTests.testDiscardFirstResult (10464 ms)
[ RUN      ] page_runner_unittest.PageRunnerTests.testHandlingOfCrashedTab
[ RUN      ] chrome://crash

http://build.chromium.org/p/chromium.mac/waterfall?builder=Mac10.6%20Tests%20(3)
http://build.chromium.org/p/chromium.mac/waterfall?builder=Mac10.7%20Tests%20(3)

Original issue's description:
> Revert "Revert of Telemetry: Last ditch effort to dump symbols on tab crashes if none are found (https://codereview.chromium.org/318123002/)"
> 
> This reverts https://codereview.chromium.org/320693002/
> 
> The original regression this caused (PageRunnerTests.testHandlingOfCrashedTab in telemetry_unittests) does not seem to be happening anymore (locally or on trybots), but please revert and let me know if it happens on the main waterfall.
> 
> TBR=tonyg,dtu
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287612

TBR=tonyg@chromium.org,dtu@chromium.org,oysteine@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/446743002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287652 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/backends/chrome/desktop_browser_backend.py

@@ -269,47 +269,31 @@ class DesktopBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
       logging.warning('minidump_stackwalk binary not found.')
       return None
 
+    symbols = glob.glob(os.path.join(self._browser_directory, '*.breakpad*'))
+    if not symbols:
+      logging.warning('No breakpad symbols found.')
+      return None
+
     with open(minidump, 'rb') as infile:
       minidump += '.stripped'
       with open(minidump, 'wb') as outfile:
         outfile.write(''.join(infile.read().partition('MDMP')[1:]))
 
     symbols_path = os.path.join(self._tmp_minidump_dir, 'symbols')
-
-    symbols = glob.glob(os.path.join(self._browser_directory, '*.breakpad*'))
-    if symbols:
-      for symbol in sorted(symbols, key=os.path.getmtime, reverse=True):
-        if not os.path.isfile(symbol):
+    for symbol in sorted(symbols, key=os.path.getmtime, reverse=True):
+      if not os.path.isfile(symbol):
+        continue
+      with open(symbol, 'r') as f:
+        fields = f.readline().split()
+        if not fields:
           continue
-        with open(symbol, 'r') as f:
-          fields = f.readline().split()
-          if not fields:
-            continue
-          sha = fields[3]
-          binary = ' '.join(fields[4:])
-        symbol_path = os.path.join(symbols_path, binary, sha)
-        if os.path.exists(symbol_path):
-          continue
-        os.makedirs(symbol_path)
-        shutil.copyfile(symbol, os.path.join(symbol_path, binary + '.sym'))
-    else:
-      logging.info('Dumping breakpad symbols')
-      generate_breakpad_symbols_path = os.path.join(
-          util.GetChromiumSrcDir(), "components", "breakpad",
-          "tools", "generate_breakpad_symbols.py")
-      cmd = [
-          sys.executable,
-          generate_breakpad_symbols_path,
-          '--binary=%s' % self._executable,
-          '--symbols-dir=%s' % symbols_path,
-          '--build-dir=%s' % self._browser_directory,
-          ]
-
-      try:
-        subprocess.check_output(cmd, stderr=open(os.devnull, 'w'))
-      except subprocess.CalledProcessError:
-        logging.warning('Failed to execute "%s"' % ' '.join(cmd))
-        return None
+        sha = fields[3]
+        binary = ' '.join(fields[4:])
+      symbol_path = os.path.join(symbols_path, binary, sha)
+      if os.path.exists(symbol_path):
+        continue
+      os.makedirs(symbol_path)
+      shutil.copyfile(symbol, os.path.join(symbol_path, binary + '.sym'))
 
     return subprocess.check_output([stackwalk, minidump, symbols_path],
                                    stderr=open(os.devnull, 'w'))