Bug 1546545: Part 1 - Properly store pointer to sandboxed DLL intercepted method r=aklotz

Bug 1533808 introduced code to intercept DLL methods that the Chromium sandbox had already intercepted.  That patch did not store the the pointer to the intercepted function in the trampoline data, as is done when intercepting other methods.

Differential Revision: https://phabricator.services.mozilla.com/D28612

--HG--
extra : moz-landing-system : lando

mozglue/misc/interceptor/PatcherDetour.h

@@ -595,13 +595,13 @@ class WindowsDllDetourPatcher final : public WindowsDllPatcherBase<VMPolicy> {
       tramp.WriteEncodedPointer(nullptr);
     });
 
-    if (PatchIfTargetIsRecognizedTrampoline(tramp, origBytes, aDest,
-                                            aOutTramp)) {
+    tramp.WritePointer(origBytes.AsEncodedPtr());
+    if (!tramp) {
       return;
     }
 
-    tramp.WritePointer(origBytes.AsEncodedPtr());
-    if (!tramp) {
+    if (PatchIfTargetIsRecognizedTrampoline(tramp, origBytes, aDest,
+                                            aOutTramp)) {
       return;
     }