[CfT] Enable ChromeForTestingAllowed policy on Android

Chrome for Testing is going to be available on Android, so
this CL adds support for the controlling policy this platform.

Bug: 40932501
Change-Id: I49ccc48895bd79f3fec105aa2c1b494fc8a69ead
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5715209
Reviewed-by: Sergey Poromov <[email protected]>
Reviewed-by: Gabriel Charette <[email protected]>
Commit-Queue: Peter Kvitek <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1329594}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index ab59f2a..0e3a1f4 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -1733,7 +1733,8 @@
                                 true);
 #endif  // BUILDFLAG(ENABLE_PDF)
 
-#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN) || \
+    BUILDFLAG(IS_ANDROID)
   registry->RegisterBooleanPref(prefs::kChromeForTestingAllowed, true);
 #endif