Remove JsonPrefStore pruning of empty values on write.

Written from https://codereview.chromium.org/12092021

The entire source code was surveyed for existing list/dict prefs for which this change could be problematic, it doesn't look like anything is relying on this internal detail of the API, see this for details: https://docs.google.com/a/chromium.org/spreadsheet/ccc?key=0AtwXJ4IPPZBAdG9rX3RTc3k5Z1pyN3U4b3d4Tkota3c#gid=0

TBR=joth (for minor android_webview side-effects)
BUG=323346

Review URL: https://codereview.chromium.org/81183005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237473 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 25 insertions, 0 deletions

diff --git a/base/values_unittest.cc b/base/values_unittest.cc
index 733c485..70acdfd 100644
--- a/base/values_unittest.cc
+++ b/base/values_unittest.cc
@@ -323,6 +323,31 @@ TEST(ValuesTest, DictionaryWithoutPathExpansion) {
   EXPECT_EQ(Value::TYPE_NULL, value4->GetType());
 }
 
+TEST(ValuesTest, DictionaryRemovePath) {
+  DictionaryValue dict;
+  dict.Set("a.long.way.down", Value::CreateIntegerValue(1));
+  dict.Set("a.long.key.path", Value::CreateBooleanValue(true));
+
+  scoped_ptr<Value> removed_item;
+  EXPECT_TRUE(dict.RemovePath("a.long.way.down", &removed_item));
+  ASSERT_TRUE(removed_item);
+  EXPECT_TRUE(removed_item->IsType(base::Value::TYPE_INTEGER));
+  EXPECT_FALSE(dict.HasKey("a.long.way.down"));
+  EXPECT_FALSE(dict.HasKey("a.long.way"));
+  EXPECT_TRUE(dict.Get("a.long.key.path", NULL));
+
+  removed_item.reset();
+  EXPECT_FALSE(dict.RemovePath("a.long.way.down", &removed_item));
+  EXPECT_FALSE(removed_item);
+  EXPECT_TRUE(dict.Get("a.long.key.path", NULL));
+
+  removed_item.reset();
+  EXPECT_TRUE(dict.RemovePath("a.long.key.path", &removed_item));
+  ASSERT_TRUE(removed_item);
+  EXPECT_TRUE(removed_item->IsType(base::Value::TYPE_BOOLEAN));
+  EXPECT_TRUE(dict.empty());
+}
+
 TEST(ValuesTest, DeepCopy) {
   DictionaryValue original_dict;
   Value* original_null = Value::CreateNullValue();