Add CHECK in case PathProviderAndroid is failing.

base/base_paths_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines base::PathProviderAndroid which replaces base::PathProviderPosix for
 // Android in base/path_service.cc.
 
 #include <limits.h>
 #include <unistd.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/path_utils.h"
 #include "base/base_paths.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/process/process_metrics.h"
 
 namespace base {
 
 bool PathProviderAndroid(int key, FilePath* result) {
   switch (key) {
     case base::FILE_EXE: {
       char bin_dir[PATH_MAX + 1];
       int bin_dir_size = readlink(kProcSelfExe, bin_dir, PATH_MAX);
       if (bin_dir_size < 0 || bin_dir_size > PATH_MAX) {
-        NOTREACHED() << "Unable to resolve " << kProcSelfExe << ".";
+        // TODO(falken): This CHECK is for debugging crbug.com/600226.
+        // Revert to NOTREACHED when the cause of the bug is understood.
+        CHECK(false) << "Unable to resolve " << kProcSelfExe
+                     << ". bin_dir_size=" << bin_dir_size
+                     << ", errno=" << errno;

[Torne, 2016/04/25 09:41:54]

Use PCHECK here instead of including errno this way - it interprets errno and
gives you a meaningful string, making the log easier to understand (also works
on windows by using GetLastError, just for reference).

I know this is just a temporary debugging thing, but it's a good general habit
;)

[falken, 2016/04/25 12:52:58]

Ah, didn't know that existed. Done. I also removed the unreachable return
statement.

         return false;
       }
       bin_dir[bin_dir_size] = 0;
       *result = FilePath(bin_dir);
       return true;
     }
     case base::FILE_MODULE:
       // dladdr didn't work in Android as only the file name was returned.
       NOTIMPLEMENTED();
       return false;
@@ skipping 14 matching lines @@
       return base::android::GetExternalStorageDirectory(result);
     default:
       // Note: the path system expects this function to override the default
       // behavior. So no need to log an error if we don't support a given
       // path. The system will just use the default.
       return false;
   }
 }
 
 }  // namespace base