Use base namespace for string16 in components and cloud_print.

components/autofill/core/browser/phone_field_unittest.cc

Index: components/autofill/core/browser/phone_field_unittest.cc
diff --git a/components/autofill/core/browser/phone_field_unittest.cc b/components/autofill/core/browser/phone_field_unittest.cc
index 44c3df66b8c3d6fee1ea6be5773e7da855cd722a..fa04f5d7c5a451baf5ab59445114580a0614d0f2 100644
--- a/components/autofill/core/browser/phone_field_unittest.cc
+++ b/components/autofill/core/browser/phone_field_unittest.cc
@@ -142,11 +142,11 @@ TEST_F(PhoneFieldTest, ThreePartPhoneNumberPrefixSuffix) {
   field.name = ASCIIToUTF16("area");
   list_.push_back(new AutofillField(field, ASCIIToUTF16("areacode1")));
 
-  field.label = string16();
+  field.label = base::string16();
   field.name = ASCIIToUTF16("prefix");
   list_.push_back(new AutofillField(field, ASCIIToUTF16("prefix2")));
 
-  field.label = string16();
+  field.label = base::string16();
   field.name = ASCIIToUTF16("suffix");
   list_.push_back(new AutofillField(field, ASCIIToUTF16("suffix3")));
 
@@ -179,7 +179,7 @@ TEST_F(PhoneFieldTest, ThreePartPhoneNumberPrefixSuffix2) {
   field.max_length = 3;
   list_.push_back(new AutofillField(field, ASCIIToUTF16("phone2")));
 
-  field.label = string16();
+  field.label = base::string16();
   field.name = ASCIIToUTF16("phone3");
   field.max_length = 4;
   list_.push_back(new AutofillField(field, ASCIIToUTF16("phone3")));