Move slow GURL Java assert to faster c++ assert

Debatable whether this assert is necessary as I can't imagine GURL ever
changing such that non-ASCII chars sneak into the output without
breaking the world, but just in case...

Bug: 1488235
Change-Id: Ic44208cc77d0caf10f0ef688195810031b1f8b77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4904227
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1204735}

url/android/gurl_android.cc

@@ -15,6 +15,7 @@
 #include "base/functional/bind.h"
 #include "base/functional/callback.h"
 #include "base/memory/ptr_util.h"
+#include "base/strings/string_util.h"
 #include "url/android/parsed_android.h"
 #include "url/third_party/mozilla/url_parse.h"
 #include "url/url_jni_headers/GURL_jni.h"
@@ -49,6 +50,10 @@ static std::unique_ptr<GURL> FromJavaGURL(JNIEnv* env,
 static void InitFromGURL(JNIEnv* env,
                          const GURL& gurl,
                          const JavaRef<jobject>& target) {
+  // Ensure that the spec only contains US-ASCII (single-byte characters) or the
+  // parsed indices will be wrong as the indices are in bytes while Java Strings
+  // are always 16-bit.
+  DCHECK(base::IsStringASCII(gurl.possibly_invalid_spec()));
   Java_GURL_init(
       env, target,
       base::android::ConvertUTF8ToJavaString(env, gurl.possibly_invalid_spec()),

url/android/java/src/org/chromium/url/GURL.java

@@ -135,8 +135,6 @@ public class GURL {
     @CalledByNative
     private void init(String spec, boolean isValid, Parsed parsed) {
         mSpec = spec;
-        // Ensure that the spec only contains US-ASCII or the parsed indices will be wrong.
-        assert mSpec.matches("\\A\\p{ASCII}*\\z");
         mIsValid = isValid;
         mParsed = parsed;
     }