[chromium linker] Check for null ParcelFileDescriptor before using it.

base/android/java/src/org/chromium/base/library_loader/Linker.java

Index: base/android/java/src/org/chromium/base/library_loader/Linker.java
diff --git a/base/android/java/src/org/chromium/base/library_loader/Linker.java b/base/android/java/src/org/chromium/base/library_loader/Linker.java
index 15968adc2a7c29d4c13c6223c7b858c8bc001ccc..d09572a559ac3efa2723e366c4884e2f5e71c13c 100644
--- a/base/android/java/src/org/chromium/base/library_loader/Linker.java
+++ b/base/android/java/src/org/chromium/base/library_loader/Linker.java
@@ -953,7 +953,8 @@ public class Linker {
             mRelroStart = in.readLong();
             mRelroSize = in.readLong();
             ParcelFileDescriptor fd = in.readFileDescriptor();
-            mRelroFd = fd.detachFd();
+            // If CreateSharedRelro fails, the OS file descriptor will be -1 and |fd| will be null.
+            mRelroFd = (fd == null) ? -1 : fd.detachFd();

[simonb (inactive), 2014/09/03 16:32:37]

Maybe reverse the condition so that the 'exception' case is last?

mRelroFd = (fd != null) ? fd.detachFd() : -1;

[whywhat, 2014/09/03 16:38:29]

Sorry,I've already checked the commit box :)
I've considered even writing a full if() statement to make it clearer (my
readability reviewer never believed in the ternary operator) but then decided
it'd be too much.

I don't have a strong opinion on this but my counterpoint would be that people
tend to better understand positive expressions rather than negative ones (e.g.
== vs != ) and it's also easier to visually parse fd.detachFd() out of the
statement since it's in the very end.

         }
 
         // from Parcelable