Store URLs in WebappDataStorage, and purge them when history is cleared.

chrome/browser/android/webapps/webapp_registry.cc

Index: chrome/browser/android/webapps/webapp_registry.cc
diff --git a/chrome/browser/android/webapps/webapp_registry.cc b/chrome/browser/android/webapps/webapp_registry.cc
index 588e3addc1e56a0602129895bf8db357899a680a..e63f5487302ab086c885f3ffc239d811ee1a01d4 100644
--- a/chrome/browser/android/webapps/webapp_registry.cc
+++ b/chrome/browser/android/webapps/webapp_registry.cc
@@ -26,6 +26,18 @@ void WebappRegistry::UnregisterWebapps(
       callback_pointer);
 }
 
+// static
+void WebappRegistry::ClearWebappHistory(const base::Closure& callback) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  uintptr_t callback_pointer = reinterpret_cast<uintptr_t>(
+      new base::Closure(callback));
+
+  Java_WebappRegistry_clearWebappHistory(
+      env,
+      base::android::GetApplicationContext(),
+      callback_pointer);
+}
+
 // Callback used by Java when all web apps have been unregistered.
 void OnWebappsUnregistered(JNIEnv* env,
                            const JavaParamRef<jclass>& klass,
@@ -35,6 +47,15 @@ void OnWebappsUnregistered(JNIEnv* env,
   delete callback;
 }
 
+// Callback used by Java when all web app last used times have been cleared.
+void OnClearedWebappHistory(JNIEnv* env,
+                                  const JavaParamRef<jclass>& klass,

[gone, 2016/03/08 22:40:39]

nit: indentation; common convention is to use clazz

+                                  jlong jcallback) {
+  base::Closure* callback = reinterpret_cast<base::Closure*>(jcallback);
+  callback->Run();
+  delete callback;
+}
+
 // static
 bool WebappRegistry::RegisterWebappRegistry(JNIEnv* env) {
   return RegisterNativesImpl(env);