Ladybird+LibWebView: Move console history tracking to ConsoleClient

This will allow other chromes to make use of history in their console
implementations.

Userland/Libraries/LibWebView/ConsoleClient.cpp

@@ -47,10 +47,44 @@ ConsoleClient::~ConsoleClient()
     m_content_web_view.on_received_console_messages = nullptr;
 }
 
-void ConsoleClient::execute(StringView script)
+void ConsoleClient::execute(String script)
 {
     print_source(script);
-    m_content_web_view.js_console_input(script);
+    m_content_web_view.js_console_input(script.to_deprecated_string());
+
+    if (m_history.is_empty() || m_history.last() != script) {
+        m_history.append(move(script));
+        m_history_index = m_history.size();
+    }
+}
+
+Optional<String> ConsoleClient::previous_history_item()
+{
+    if (m_history_index == 0)
+        return {};
+
+    --m_history_index;
+    return m_history.at(m_history_index);
+}
+
+Optional<String> ConsoleClient::next_history_item()
+{
+    if (m_history.is_empty())
+        return {};
+
+    auto last_index = m_history.size() - 1;
+
+    if (m_history_index < last_index) {
+        ++m_history_index;
+        return m_history.at(m_history_index);
+    }
+
+    if (m_history_index == last_index) {
+        ++m_history_index;
+        return String {};
+    }
+
+    return {};
 }
 
 void ConsoleClient::clear()

Userland/Libraries/LibWebView/ConsoleClient.h

@@ -9,6 +9,7 @@
 #include <AK/DeprecatedString.h>
 #include <AK/Function.h>
 #include <AK/Span.h>
+#include <AK/String.h>
 #include <AK/StringView.h>
 #include <AK/Vector.h>
 #include <LibWebView/Forward.h>
@@ -20,7 +21,10 @@ public:
     explicit ConsoleClient(ViewImplementation& content_web_view, ViewImplementation& console_web_view);
     ~ConsoleClient();
 
-    void execute(StringView);
+    void execute(String);
+
+    Optional<String> previous_history_item();
+    Optional<String> next_history_item();
 
     void clear();
     void reset();
@@ -50,6 +54,9 @@ private:
     };
     Vector<Group> m_group_stack;
     int m_next_group_id { 1 };
+
+    Vector<String> m_history;
+    size_t m_history_index { 0 };
 };
 
 }