Improves Android support (by David Turner).

src/gtest-port.cc

@@ -531,11 +531,25 @@ class CapturedStream {
     filename_ = temp_file_path;
 # else
     // There's no guarantee that a test has write access to the current
-    // directory, so we create the temporary file in the /tmp directory instead.
-    // We use /tmp on most systems, and /mnt/sdcard on Android. That's because
-    // Android doesn't have /tmp.
+    // directory, so we create the temporary file in the /tmp directory
+    // instead. We use /tmp on most systems, and /sdcard on Android.
+    // That's because Android doesn't have /tmp.
 #  if GTEST_OS_LINUX_ANDROID
-    char name_template[] = "/mnt/sdcard/gtest_captured_stream.XXXXXX";
+    // Note: Android applications are expected to call the framework's
+    // Context.getExternalStorageDirectory() method through JNI to get
+    // the location of the world-writable SD Card directory. However,
+    // this requires a Context handle, which cannot be retrieved
+    // globally from native code. Doing so also precludes running the
+    // code as part of a regular standalone executable, which doesn't
+    // run in a Dalvik process (e.g. when running it through 'adb shell').
+    //
+    // The location /sdcard is directly accessible from native code
+    // and is the only location (unofficially) supported by the Android
+    // team. It's generally a symlink to the real SD Card mount point
+    // which can be /mnt/sdcard, /mnt/sdcard0, /system/media/sdcard, or
+    // other OEM-customized locations. Never rely on these, and always
+    // use /sdcard.
+    char name_template[] = "/sdcard/gtest_captured_stream.XXXXXX";
 #  else
     char name_template[] = "/tmp/captured_stream.XXXXXX";
 #  endif  // GTEST_OS_LINUX_ANDROID