lshal: ListCommand::getPidInfo should be cached.

The function parses a big file and its result should be cached.
Add ListCommand::getPidInfoCached, which is a cached version
of this function.

Test: lshal_test
Change-Id: I03d8f149bf67b1512be431a3c4c29e83f7743a2f
diff --git a/cmds/lshal/test.cpp b/cmds/lshal/test.cpp
index bb23b2c..7d87d6d 100644
--- a/cmds/lshal/test.cpp
+++ b/cmds/lshal/test.cpp
@@ -196,6 +196,9 @@
         return ListCommand::dumpVintf(out);
     }
     void internalPostprocess() { ListCommand::postprocess(); }
+    const PidInfo* getPidInfoCached(pid_t serverPid) {
+        return ListCommand::getPidInfoCached(serverPid);
+    }
 
     MOCK_METHOD0(postprocess, void());
     MOCK_CONST_METHOD2(getPidInfo, bool(pid_t, PidInfo*));
@@ -355,6 +358,13 @@
     sp<MockServiceManager> passthruManager;
 };
 
+TEST_F(ListTest, GetPidInfoCached) {
+    EXPECT_CALL(*mockList, getPidInfo(5, _)).Times(1);
+
+    EXPECT_NE(nullptr, mockList->getPidInfoCached(5));
+    EXPECT_NE(nullptr, mockList->getPidInfoCached(5));
+}
+
 TEST_F(ListTest, Fetch) {
     EXPECT_EQ(0u, mockList->fetch());
     std::array<std::string, 6> transports{{"hwbinder", "hwbinder", "passthrough",