Support multiple locales string for accept language list

chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java
index 06a4457c356727c274e22c680ef729c36e043e7c..faeb411d56a1f262a84696eac512e1300fcecb7f 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/physicalweb/PwsClientImplTest.java
@@ -89,6 +89,17 @@ public class PwsClientImplTest extends InstrumentationTestCase {
     }
 
     @SmallTest
+    public void testMultipleLanguageTagIsPrepended() {
+        String locale = "aa_AA,bb_BB";

[ksk1, 2016/10/06 08:15:22]

How about having a test for multiple locales has same language code like
"aa_AA,bb_BB,bb_XX"?

[Yirui Huang, 2016/10/07 04:14:56]

Thanks for pointing out this case. A language code should only be inserted after
the last languageTag that contains that language.
Here is the example it should be:
locales = "aa_AA,aa_BB",acceptLanguages = "xx-XX,xx". output =
"aa-AA,aa-BB,aa,xx-XX,xx".

I tried to fix it by checking the rest of locales that have not been inserted
yet. (from off line discussion with nona@) However, I also noticed that in some
previous test cases, original languageList appeared to be "xx-XX,xx,xx-YY",
which should not happen under this implementation, therefore I applied changes
on them as well.

+        String languageList = "xx-XX,xx,xx-YY";
+
+        // Should prepend the language tag "aa-AA" as well as the language code "aa".
+        String languageListWithTag = PwsClientImpl.prependToAcceptLanguagesIfNecessary(locale,
+                languageList);
+        assertEquals("aa-AA,aa,bb-BB,bb,xx-XX,xx,xx-YY", languageListWithTag);
+    }
+
+    @SmallTest
     public void testLanguageTagIsPrependedWhenListContainsLanguageCode() {
         String locale = new Locale("xx", "XX").toString();
         String languageList = "xx-YY,xx";
@@ -129,6 +140,17 @@ public class PwsClientImplTest extends InstrumentationTestCase {
     }
 
     @SmallTest
+    public void testMultiLanguageTagNotPrependedWhenUnnecessary() {
+        String locale = "xx-XX,yy-YY";
+        String languageList = "xx-XX,xx,yy-YY,yy";
+
+        // Language list should be unmodified since the tag is already present.
+        String languageListWithTag = PwsClientImpl.prependToAcceptLanguagesIfNecessary(locale,
+                languageList);
+        assertEquals(languageList, languageListWithTag);
+    }
+
+    @SmallTest
     public void testAcceptLanguageQvalues() {
         String languageList = "xx-XX,xx,xx-YY,zz-ZZ,zz";